There are6,420 unique four-letter words found across just two dictionaries, so that's not nearly all of them. Unless you mean the other "four-letter words." In either case, they can't be listed here.
avow, brow, blow, crow, dhow, enow, flow, grow, know, meow, prow, plow, stow, slow, trow
nngiuy85uy8567u894 5u89ugi54
atomitematopstabstagstarstemstepstewstaystirstopstunstubstudstewstow
four (4) letter word:yoyo.seven (7) letter word:yatobyo.
Some four letter words that start with U are:uglyulnaundountouponureaurgeused
See related links for a list of official Scrabble 2-letter words.
Elmo
bookboombootcookcoolcoopcootdoorgoodgoongoophoodhookhooplookloonloomlooplootmoodmoonmoornookpoofpoorpoolrootrookroofroomsoonsoottoottooktoolwoodwoolwoofzoom
Lust
egad,
party... part arty
Quid, quip, quad, aqua.
Some four letter words ending with M:Comment: The list below contains many instances that are not words in standard English at all.Adamahemahomahumakimalemalumanamanamarumasematombalmbarmbeambermboombrambrimcaamcalmcaumchamchamchumclamclemclemcoomcormcramcromcrumculmdeemdermdiemdoomdormdoumdramdrumduimedamejamemimenametymexamfarmfilmfirmflamflemfoamformframfrimfromgaumgawmgermgeumgeumglamglomglumgramgrimgrumhaemharmhawmhelmholmimamitemjermjoomkasmklamklomkulmleamloamloomlyammaammaimmalmmarmmeumnaamnaimneemnoamnormnormodumogamogumolamonymovumpalmpermpilmplimplumpoempramprimpromreamreemreimriemroamroomsaimsalmsaumscamscumseamseemshamshamshimsiamsiumskimslamslimslumsnumsoamsoumspamstamstemstimstumsuumswamswimswomswumtaumteamteemtermthemtiamtoomtramtrimturmutumwarmweamwhamwhimwhomwoomwormyarmyelmyirmzoom
your yellow yacht ...