There are over 100 possibilities:
Do u mean a u? If so A Haiku maybe which is a poem with 5-7-5 syllables.
Alibis, attain, auntie, bandit, bionic, caddie, elicit and garlic are 6 letter words. Additional words include hippie, kiddie, muffin, outbid, remain and studio.
Puppy
Examples of 5 letter words with the second letter 'u' are:augerburntcurseduncedustyfudgefungifunnyguessguestguilthumanhumorjudgekudzulunchlurchmuralmusicnudgenurseoughtpunchqueenquellquestrummyrumorruralsuavesunnysushitulletumorwurstyuccayummy
Strait
slope
quest...
Alter
braintrainframecreamdream
Fungi
dummy
Some five letter words with the second letter U are:audioaugerbuglebunchcubiccurrydummydutchfudgeguanoguidehumidjudgekudzulucidlunchmusicnudgenuttyouterpulsepursequietquiltrustysupertuliptunicwurstyucca
Five letter words with second letter x are:excelexertextraaxiomexpel
Some five letter words with the second letter A are:BaconbadgebanjoCadrecandyCanondancedaffydaisyeagerearlyearthfablefacetfaithgablegamuthabithairyhappyjauntkabobkayakkazoolabellancelaserMagmamatchmaybenachonastynaveloasispaperparchpartyrabidradioraisesaladsaltySatantabletainttalonvaletvalidvalvewaistwagonwateryachtyahooZaire