Beachhead, bearskin, bedpan, bedroom, bedspread, beefless, beeswax, befriend, bellhop, beltless and beltway are compound words. They begin with the letters be.
Fallback is a compound word. Falloff and fallout are compound words.
The answer is become.
teardrop gumdrop raindrop dewdrop backdrop
Doable
One such word is whenever.
zebralicious
airtimeanytimebedtimedowntimelunchtimemealtimeovertimeplaytimesometimespringtimesummertimetimebasetimeouttimesharewintertime
Snail
roommate
backbonebackgroundballparkbaseballbaseboardbasketballbathhousebathtubbathwaterbirdhousebirthdaybirthmarkbirthrightblackbirdblackboardblackmailbloodbathbookmarkbookshelfbluebellbluebirdblueprintboyhoodbrainwavebreadwinnerbreakwaterbrownstonebutterball
"Lukewarm."
maidness