Some three letter words with the second letter W are:awleweoweowlowntwo
Some six letter words with p as the second letter are opener, operas, sparse, and apiece.
Some four letter words with second letter U and fourth letter O are:autoeurojudokudoouzo
Five letter words with second letter x are:excelexertextraaxiomexpel
Skunk
addition
The letter 'n'. not very mathematical.
Some four letter words with a second letter U are:auraburncurbcuredulldumbeurofundguruhugejumpjunklumpluremuchmutenudeoustpullpurepushrulerumpruinruserushrustsuchsurftune
Some three letter words with the second letter W are:awleweoweowlowntwo
JOINT
Some words that have the second letter U are:augustaurabullbutchercuddlecutdunedurableeuphemismEuropefullfungungutterhurlhutjudgejumpjuryjustkudoslunchluremuchmudmullmurdernudgenullnuptialouchouroutpuddingpunchpushquailquarryquartquartzquoteruderuinrulerushruthlesssuddensuitsullensuppersuretunneltummyturkeyvulnerablevulture
Some six letter words with p as the second letter are opener, operas, sparse, and apiece.
Some four letter words with second letter U and fourth letter O are:autoeurojudokudoouzo
Some words (I don't know them all) with the second letter U:aughtautobuckburnbuttercurecutcuteduckdungeondurableeurekaEuropefunnyfurygumballguruhugehumblejumpjuniperjunkkudoskukuiluckyluminousmudmunchmunicipalnumbnumerousnuttyoughtouroutsidepullpunishpurequietquitruggedrumorrushsuddenlysugarsureturnturtletutorZulu
Some five letter words with the second letter U are:audioaugerbuglebunchcubiccurrydummydutchfudgeguanoguidehumidjudgekudzulucidlunchmusicnudgenuttyouterpulsepursequietquiltrustysupertuliptunicwurstyucca
Some five letter words with the second letter A are:BaconbadgebanjoCadrecandyCanondancedaffydaisyeagerearlyearthfablefacetfaithgablegamuthabithairyhappyjauntkabobkayakkazoolabellancelaserMagmamatchmaybenachonastynaveloasispaperparchpartyrabidradioraisesaladsaltySatantabletainttalonvaletvalidvalvewaistwagonwateryachtyahooZaire
Five letter words with second letter x are:excelexertextraaxiomexpel