hunk n.1

1680s (in hump-backed), of uncertain origin; perhaps from Dutch homp "lump," from Middle Low German hump "bump," from Proto-Germanic *hump-, from PIE *kemb- "to bend, turn, change, exchange" (see change (v.)). Replaced, or perhaps influenced by, crump, from Old English crump.

A meaning attested from 1901 is "mound in a railway yard over which cars must be pushed," which might be behind the figurative sense of "critical point of an undertaking" (1914). By 1957, hump day was in use in reference to the mid-point of a training program or course; it was extended to "Wednesday," as the mid-point of the work-week, by 1987.

also honkey, derogatory word for "white person," by 1967, African-American vernacular, of unknown origin, perhaps from late 19c. hunky "East-Central European immigrant," which probably is a colloquial shortening of Hungarian (compare hunk (n.2)). Honky in the sense of "factory hand" is attested by 1946 in blues slang. A connection to honky-tonk also is possible.