Fallback is a compound word. Falloff and fallout are compound words.
The answer is become.
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One such word is whenever.
zebralicious
airtimeanytimebedtimedowntimelunchtimemealtimeovertimeplaytimesometimespringtimesummertimetimebasetimeouttimesharewintertime
Doable
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Snail
roommate
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"Lukewarm."