"Patchwork", meaning made up of individual small parts for different sources, such as a "patchwork quilt".
Fallback is a compound word. Falloff and fallout are compound words.
The answer is become.
A compound word starting with "drop" is "dropkick."
Doable
airtimeanytimebedtimedowntimelunchtimemealtimeovertimeplaytimesometimespringtimesummertimetimebasetimeouttimesharewintertime
One such word is whenever.
zebralicious
Balloon.
backbonebackgroundballparkbaseballbaseboardbasketballbathhousebathtubbathwaterbirdhousebirthdaybirthmarkbirthrightblackbirdblackboardblackmailbloodbathbookmarkbookshelfbluebellbluebirdblueprintboyhoodbrainwavebreadwinnerbreakwaterbrownstonebutterball
maidness
Bankteller
mousehouse