This section is from the book "Hill's Manual Of Social And Business Forms: A Guide To Correct Writing", by Thos. E. Hill. Also available from Amazon: Hill's Manual Of Social And Business Forms: The How-To-Do-Everything Book Of Victorian America.
Simple - weak, silly, artless, foolish, unwise, stupid, plain, single.
Simply - solely, merely, only.
Since - for, as, inasmuch, after.
Sincere - true, honest, frank, upright, incorrupt, plain.
Singular - particular, eccentric, odd, strange, remarkable, rare, scarce.
Situation - place, position, employment, site, locality, case, condition, plight.
Skillful - expert, adroit, adept, dexterous, accomplished.
Slander - defame, vilify, calumniate, detract.
Slavery - servitude, bondage, captivity.
Slender - slight, slim, fragile, thin.
Slow - tardy, dilatory, tedious, dull.
Small - little, minute, diminutive, narrow, infinitesimal.
Smooth - easy, mild, bland, even, level.
Smother - suffocate, stifle, suppress, conceal.
Snarling - snappish, waspish, surly.
Sober - grave, moderate, temperate, abstemious.
Social - sociable, companionable, convivial, familiar.
Society - fellowship, company, congregation, association, community.
Soft - flexible, ductile, yielding, pliant, mild, compliant.
Solicit - request, ask, entreat, implore, beg, beseech, supplicate, importune.
Solicitation - entreaty, invita-tion, importunity.
Solicitude - care, earnestness, anxiety.
Solid - enduring, firm, hard, substantial.
Solitary - sole, alone, desolate, only, lonely, remote, retired.
Soothe - quiet, compose, appease, calm, pacify, assuage, tranquil-ize.
Sorrow - trouble, grief, affliction.
Sort - order, kind, species.
Sound - tone. firm, whole, hearty, healthy, sane.
Sour - tart, acid, acrimonious, sharp.
Source - head, origin, fountain, cause, spring, reason.
Spacious - capacious, ample, large.
Sparkle - glitter, glisten, shine, glare, radiate, corruscate.
Speak - utter, talk, articulate, pronounce, converse, say, tell, recite, relate.
Species - order, kind, class, sort.
Specific - definite, particular, special.
Specimen - sample, model, pattern.
Spectator - beholder, observer, auditor.
Speech - oration, address, lecture, harangue, sermon.
Speechless - dumb, silent, mute.
Spend - expend, exhaust, dissipate, squander, waste.
Sphere - orb, circle, globe.
Spirited - quick, animated, ardent, vivacious, active.
Spiritual - ethereal, immaterial, unearthly, incorporeal.
Spite - pique, malice, grudge, ma-lignity, hate.
Splendid - superb, magnificent, grand, sublime, heavenly.
Splendor - magnificence, luster, brightness, brilliancy.
Splenetic - peevish, melancholy, morose, sullen, gloomy, fretful.
Sport - play, game, amusement, pastime, diversion, recreation.
Spotless - faultless, unblemished, blameless, unsullied, clear, untarnished, pure, innocent, stainless.
Spread - distribute, diffuse, circulate, expand, disperse, disseminate, propagate, scatter, dispense, sow.
Spring: - leap, arise, start, flow, proceed, emanate, jump, issue.
Sprinkle - bedew, water, scatter, besprinklc. Sprout - vegetate, germinate, bud. Stability - fixedness, continuity, steadiness, firmness. Stain - mar, soil, tarnish, blemish, blot, flaw, spot, speck, tinge, color, discolor.
Stammer - hesitate, stutter, falter.
Stamp - mark, print, impress.
Standard - test, rule, criterion.
State - situation, condition, position, plight, predicament.
Station - place, situation, post, position.
Stay - dependence, reliance, staff, prop, abide, remain, continue, delay, hinder, support.
Sterility - barrenness, unfruitful-ness.
Stern - unfeeling, severe, austere, strict, cold, rigid, rigorous.
Still - quiet, calm, silent, appease, assuage, lull, pacify.
Stimulate - arouse, excite, incite, urge, impel, encourage, instigate.
Stock - supply, collection, fund, accumulation, store, provision, cattle.
Stop - rest, intermission, vacation, cessation, delay, hinder, impede, check.
Story - tale, anecdote, incident, memoir.
Straight - direct, immediate.
Strange - unusual, curious, odd. singular, surprising, eccentric.
Stratagem - deception, cheat, artifice, fraud, trick, imposture, delusion.
Strength - potency, authority, power, force, might. Strict - precise, exact, particular, accurate, nice, severe, harsh, rigorous, stern.
Strife - disagreement, dissension, discord, contest.
Strong - able, powerful, robust, stout, vigorous, firm, muscular, hardy.
Style - custom, mode, manner, phraseology, diction.
Subdue - vanquish, conquer, overcome, subjugate, subject, surmount.
Subject - control, liable, exposed, object, matter, material.
Subjoin - attach, connect, annex, affix.
Sublime - lofty, elevated, great, exalted, grand, magnificent.
Submissive - obedient, yielding, humble, compliant.
Subordinate - subject, subservient, inferior.
Subsistence - livelihood, living, sustenance, maintenance, support.
Substantial - reliable, strong, solid, stout, real, responsible.
Subtle - sly, artful, cunning, deceitful, crafty, wily, perfidious, insidious, arch, acute, fine.
Subtract - withdraw, deduct, take from.
Subvert - ruin, overthrow, reverse, controvert, invert, reverse.
Successful - prosperous, lucky, winning, fortunate.
Succession - series, order, continuance.
Succor - defend, help, aid, assist, relieve.
Sudden - unexpected, unlooked for, unanticipated, hasty.
Suffer - endure, tolerate, permit, bear, allow.
Suffocate - smother, choke, stifle.
Sufficient - plenty, abundance, enough, competent, adequate.
Suffrage - vote, ballot, aid, voice.
Suggest - propose, insinuate, hint, allude, intimate.
Suitable - appropriate, fit, becoming, agreeable, expedient.
Suitor - beau, wooer, lover, petitioner.