The most common meaning of honky is "white person". According to Communicating offense: the sordid life of language use:
…the word “honky” is a derogatory term for a Caucasian. Anyone who claims to be using it in a non-derogatory sense is also making a linguistic error.
There is, however, another definition for honky (noun):
Freq. with capital initial. An immigrant from central or eastern Europe, esp. one working as a manual labourer. Hence occas. more generally: any person employed in manual or unskilled work.
This definition is "rare" and "chiefly historic in later use". It may not seem offensive, but it was often used alongside other slurs like dago, wop, and bohunk.
Between the two definitions, OED says it's "chiefly derogatory".