Four letter words that can be made from the letters in 'syringe' are:
Four letter words that can be made from the letters 'nfwade' are:anewaweddawndeafdeanfadefawnfendwadewandwaneweanwend
Jerk.
dry
Four letter words that can be made from the letters 'monastery' are:amenantearmyatomearneasteasymanemanymareMarsmartmastmatemeanmeatmesamoanmoatmoremostmotenamenearneatnestnosenosynoteomenrantratereamrentrestroamroanroserosyrotesamesanesateseamsearseatsentsnotsoarsomesoresortstarstaystemtametaretarntaroteamteartermterntometonetoretorntramtraytreytroytsaryarnyearyore
Some four letter words you can make from the word "syllabus" are ally, busy, bass, bull, and ball.
team mate tame
You can do even better than just five words!arborardorbardsbarfsbaudsboardboarsborasbradsbroadburasburdsburroburrsbursadarbsdaubsdobradorrsdorsadouradrabsdrubsdurasdurosdurradurrsfadosfardsfarosforbsfordsfoursfraudfubarfurorroadsroarssarodsofarsudorsurra
Four letter words that can be made from the letters in Merry Christmas are:acheacidacmeacrearcharmycarecartcasecashcastcharcatecitecramcysteacheasteasyemiremithairhareharmhatehearheathirehissitchitemmacemachmareMarsmartmashmastmatemathmeanmeatmeshmessmicamimemiremissmistmitemythraceracyrarerashratereamrearrestricerichrimeriseritesamesashsatescamscarscatseamseatsectshamshimshirrsiresitestarstaystemstirtametareteamteartermtestthemtheythistiertimetire, tyretramtraytrimyear
Four letter words that can be made from the letters 'cat in the hat' are:acheacneantecanecant (also can't)catecentchatchinchitciteeachetchhatehathheathintinchitchneatnicetactteattentthanthatthenthintinetint
Four letter words that can be made with the letters 'irbegd' are:bergbidebierbirdbredbriebrigdiredribgirdgridrideThose letters will also spell the word 'bridge'.
Post, as in postcard and posthaste.
That is a trick question. You can't make a four letter word using all five vowels.