2 letters:
st

3 letters:
eat, st.

4 letters:
amit, beat, beet, deet, feat, feet, heat, leet, meet, mete, neat, neet, peat, peet, pete, piet, seat, teat, teet, veit

5 letters:
abete, apiit, beete, bleat, breet, breit, cheat, cleat, cleet, creat, crete, cuite, diete, elite, epeat, exeat, fleet, flete, freet, freit, frite, gleet, greet, grete, griet, ideat, keitt, krete, lalit, leete, leite, miete, mitte, niete, peete, pleat, plete, prete, sceat, seite, sheat, sheet, siete, skeat, skeet, skete, sleat, sleet, smeat, speet, steat, steet, suite, sweet, swete, tdeat, theat, tiete, treat, treet, tveit, tweet, vliet, wheat

6 letters:
admete, afreet, afrite, ariete, asciet, bemeet, bemete, bufete, canete, cliett, curiet, d-beat, deceit, defeat, delete, effete, efreet, faceit, filete, gamete, hieght, jobete, jubeat, kriete, lanete, maarit, orgeat, petite, piette, pleite, poteat, puneet, quiett, receit, reheat, repeat, reseat, sanjit, skeete, steat-, street, sweatt, tacite, threet, unbeat, unmeet, unseat, upbeat, valete

7 letters:
abigeat, abijeet, accrete, agamete, amfleet, arboret, athlete, bigfeet, byfleet, c-suite, carrete, chafete, ciii-dt, compete, conceit, decreet, decrete, deplete, disseat, dogmeat, entreat, escheat, estreat, excheat, excrete, extreat, fiorite, floreat, forwete, guerite, intreat, ippolit, juguete, keyseat, kinjite, laffite, magneet, martite, mellite, mesquit, munjeet, murveit, negrete, nutmeat, offbeat, opplete, outfeat, overeat, papeete, pigmeat, planeet, poblete, preheat, ranjeet, receipt, recheat, regreet, replete, retreat, retweet, secrete, shumeet, streett, suffete, sunnite, surbeat, tafheet, threatt, thweatt, to-beat, umfleet, unpleat, unsweet, up-beat, volbeat, webfeet, wfty-dt, wlii-dt

8 letters:
afrobeat, albacete, alfinete, ammocete, appsheet, backbeat, backseat, bakemeat, balliett, bedsheet, benfleet, bluebeat, browbeat, bushmeat, bystreet, calcrete, clubfeet, compleat, compleet, complete, conchite, concrete, congreet, cowwheat, crabmeat, crowfeet, deadbeat, discreet, discrete, downbeat, drumbeat, dry-beat, duckmeat, elaolite, eurobeat, ewigkeit, filarete, flatfeet, flysheet, forefeet, galerite, halbzeit, helpmeet, hoofbeat, illtreat, jumpseat, longleat, lorikeet, loveseat, maleseet, maliseet, maltreat, manolete, mathlete, melilite, mesquite, mistreat, moth-eat, netsuite, newsbeat, nonsweet, norfleet, notwheat, obsolete, off-beat, oogamete, ookinete, orangeat, outbleat, outcheat, overheat, overneat, parakeet, paysheet, peerweet, peetweet, pretreat, re-treat, re-tweet, shilajit, silcrete, sunsweet, tambreet, trabeate, two-beat, undelete, upstreet, vanfleet, vanvleet, vanvliet, wikifeet, wingbeat

9 letters:
acre-feet, afterheat, alphabeat, anaxarete, beresheet, biathlete, blackfeet, bracteate, breakbeat, bridgette, buckwheat, by-street, celestite, chokoleit, clipsheet, dangaleat, datasheet, dead-heat, decollete, denticete, dopesheet, drawsheet, dustsheet, entermete, factsheet, flowsheet, forcemeat, foresheet, four-peat, freakbeat, freesheet, heartbeat, hempcrete, hemstreet, hootsuite, horsefeet, horsemeat, ill-treat, isogamete, johannite, lunchmeat, mainsheet, maletreat, manesheet, margarete, margarite, millerite, mincemeat, misrepeat, molcajete, mysticete, nanosheet, navarrete, newssheet, on-street, outstreet, parrakeet, paupiette, phytolite, poursuite, semisweet, sheepmeat, shotcrete, slipsheet, splayfeet, splitfeet, starfleet, sugarbeet, superfete, superheat, sweetmeat, swingbeat, tholeiite, threepeat, timesheet, treesweet, ultrabeat, weet-weet, wellfleet, worksheet, worldbeat, zoogamete

10 letters:
asynartete, backstreet, baked-meat, bellycheat, bradstreet, broadsheet, court-leet, dicky-seat, draw-sheet, ebracteate, greensheet, grubstreet, heat-treat, incomplete, inconcrete, indiscreet, indiscrete, londonbeat, longstreet, mainstreet, marguerite, marquerite, mercy-seat, merseybeat, mince-meat, misconceit, misentreat, news-sheet, noncompete, nutrasweet, odontocete, off-street, outcompete, overstreet, p-complete, preconceit, scoresheet, shortsheet, silverbeet, slip-sheet, smartsheet, smartsuite, spoon-meat, steam-heat, storm-beat, tenderfeet, three-peat, uncomplete, undiscreet, wallstreet, watervliet, wholewheat, wingstreet

11 letters:
adipocerite, ai-complete, alpha-sheet, back-street, bittersweet, blackstreet, broadstreet, chargesheet, cloudstreet, countryseat, dankbarkeit, dickey-seat, dickie-seat, genauigkeit, greenstreet, groundsheet, high-street, honey-sweet, jatin-lalit, meadowsweet, monchiquite, non-compete, np-complete, officesuite, self-deceit, short-sheet, spreadsheet, stonestreet, vandervliet, venturebeat, whole-wheat, wintersweet

12 letters:
aplanogamete, autocomplete, baumhauerite, bitter-sweet, charge-sheet, countreplete, entire-wheat, heterogamete, self-conceit, spinnbarkeit, testcomplete

13 letters:
eindeutigkeit, ferroconcrete, gerechtigkeit, notwendigkeit, schwierigkeit, voiceoverpete, winding-sheet

14 letters:
co-np-complete, ferro-concrete, fettleibigkeit, tekkonkinkreet, trick-or-treat

15 letters:
all-you-can-eat, geschwindigkeit, pspace-complete, serpentwithfeet, turing-complete

16 letters:
arbeitslosigkeit

17 letters:
chester-le-street, off-balance-sheet

18 letters:
control-alt-delete