Yes, masthead is a compound word, as both "mast" and "head" are words.
maidness
without withhold within
hamburger, hamstring
lamp-post -------- Lamp-shade
board
The compound word of "school head" is "schoolhead."
Fallback is a compound word. Falloff and fallout are compound words.
The answer is become.
teardrop gumdrop raindrop dewdrop backdrop
Doable
airtimeanytimebedtimedowntimelunchtimemealtimeovertimeplaytimesometimespringtimesummertimetimebasetimeouttimesharewintertime
One such word is whenever.
zebralicious
compound word for back,short,watch
Yes, masthead is a compound word, as both "mast" and "head" are words.
The examples provided are not compound words.