"covering for the foot and lower leg," early 14c., from Old French bote "boot" (12c.), with corresponding words in Provençal, Spanish, and Medieval Latin, all of unknown origin, perhaps from a Germanic source. Originally of riding boots only.
From c. 1600 as "fixed external step of a coach." This later was extended to "low outside compartment used for stowing luggage" (1781) and hence the transferred use, of motor vehicles, in Britain, where American English has trunk (n.1).
Boot-black "person who shines boots and shoes" is from 1817; boot-jack "implement to hold a boot by the heel while the foot is drawn from it" is from 1793. Boot Hill, U.S. frontier slang for "cemetery" (1893, in a Texas panhandle context) probably is an allusion to dying with one's boots on. An old Dorsetshire word for "half-boots" was skilty-boots [Halliwell, Wright].
word-forming element meaning "lacking, cannot be, does not," from Old English -leas, from leas "free (from), devoid (of), false, feigned," from Proto-Germanic *lausaz (cognates: Dutch -loos, German -los "-less," Old Norse lauss "loose, free, vacant, dissolute," Middle Dutch los, German los "loose, free," Gothic laus "empty, vain"), from PIE root *leu- "to loosen, divide, cut apart." Related to loose and lease.
"profit, use," Old English bot "help, relief, advantage; atonement," literally "a making better," from Proto-Germanic *boto (see better (adj.)). Compare Old Frisian bote "fine, penalty, penance, compensation," German Buße "penance, atonement," Gothic botha "advantage, usefulness, profit." Now mostly in phrase to boot (Old English to bote), indicating something thrown in by one of the parties to a bargain as an additional consideration.
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<a href="https://www.etymonline.com/word/bootless">Etymology of bootless by etymonline</a>
Harper, D. (n.d.). Etymology of bootless. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/bootless