3 letters:
app, gap, hap, lap, map, nap, pap, rap, sap, tap, yap, zap

4 letters:
asap, capp, chap, clap, crap, dapp, flap, frap, gapp, giap, happ, kapp, mapp, napp, papp, rapp, sapp, shap, slap, snap, tapp, trap, wrap, yapp, zapp

5 letters:
aacap, adcap, ancap, ascap, aslap, astap, atrap, attap, bglap, c-cap, canap, cappe, chapp, clapp, conap, cscap, decap, dolap, dovap, dulap, encap, frapp, g-rap, happe, hicap, holap, ianap, intap, irlap, ismap, janap, kappe, klapp, knapp, krapp, lappe, mappe, mcmap, micap, milap, mocap, molap, nappe, nicap, nocap, nofap, nsdap, pacap, pappe, phrap, potap, rappe, recap, remap, rocap, rolap, scrap, secap, shapp, shrap, sinap, slapp, snapp, stapp, strap, tappe, tefap, thrap, trapp, uncap, unhap, vicap, wolap

6 letters:
aercap, affrap, arcmap, attrap, barcap, beclap, belnap, betrap, bewrap, bitmap, burlap, catnap, chappe, climap, cohmap, comnap, corcap, dewlap, dognap, doolap, earcap, earlap, entrap, enwrap, etappe, fodmap, frappe, gelcap, grappe, gukbap, hubcap, icecap, intrap, inwrap, isomap, keycap, kidnap, kitsap, klappe, knappe, laplap, madcap, mbappe, medcap, mencap, midcap, milsap, mipmap, mishap, mobcap, mudcap, nadcap, neshap, niacap, p-trap, pixmap, pregap, redcap, redmap, rescap, rewrap, riprap, satrap, schapp, setapp, skycap, strapp, tencap, toecap, toxmap, trappe, unicap, unisap, unsnap, unwrap, vishap, yonhap

7 letters:
alu-cap, automap, baaskap, bandgap, bersiap, bit-map, bluecap, caltrap, cantrap, dirtnap, dropcap, earflap, echappe, eyeflap, flytrap, forwrap, gametap, genapap, genappe, hoodcap, huffcap, hwangap, kneecap, kylchap, libpcap, lovemap, mantrap, mid-cap, milkcap, millsap, mob-cap, ms-chap, mudflap, nearmap, nukemap, overlap, podsnap, pop-rap, rattrap, realcap, rip-rap, roadcap, roadmap, rootcap, schappe, schlapp, schnapp, shiplap, sitemap, snowcap, specmap, stopgap, suntrap, t-strap, tap-tap, thewrap, tun/tap, unstrap, varicap, waxycap, westcap, widegap, wiretap

8 letters:
attrappe, baasskap, backslap, backwrap, beartrap, blackcap, bullcrap, claptrap, dimetapp, ettercap, firetrap, flat-cap, foolscap, giftwrap, glooscap, handclap, handicap, imagemap, interlap, itk-snap, ketchapp, knee-cap, lagnappe, lightcap, lightmap, livetrap, man-trap, mau5trap, microcap, milk-cap, mini-map, moontrap, multimap, multitap, nightcap, nordkapp, photomap, pop-trap, rastacap, rat-trap, scullcap, semarnap, skullcap, smallcap, snipsnap, spamtrap, stop-gap, superzap, underlap, waldrapp, whatsapp, whitecap, wordwrap

9 letters:
afterclap, backstrap, boobytrap, bootstrap, bottlecap, chinstrap, clickwrap, cloth-cap, cornercap, deathtrap, draintrap, flip-flap, gift-wrap, goldfrapp, guttatrap, heightmap, honeytrap, housewrap, jockstrap, lagniappe, large-cap, micro-cap, mousetrap, night-cap, priestcap, screencap, skull-cap, small-cap, snip-snap, soundtrap, sparadrap, tarnkappe, vibraslap

10 letters:
after-clap, bitch-slap, blackstrap, booby-trap, brandysnap, click-wrap, gingersnap, hukbalahap, nachtkrapp, rattletrap, shrinkwrap, shufflecap, steel-trap, watchstrap, wentletrap

11 letters:
bokkeum-bap, choke-strap, ginnungagap, rawoop-snap, semordnilap, shrink-wrap, thunderclap, wrestlecrap

12 letters:
thunder-clap

13 letters:
novochlorocap, openstreetmap

14 letters:
openweathermap, slip-slop-slap

15 letters:
corona-warn-app

2 letters:
ab

3 letters:
gab, nab, jab, dab, fab, tab, cab, lab

4 letters:
slab, stab, scab, grab, crab, flab, drab

6 letters:
prefab, lablab

7 letters:
pedicab