"to complain, whine," 1953 (implied in kvetching), from Yiddish kvetshn, literally "squeeze, press," from German quetsche "crusher, presser." As a noun, from 1936 as a term of abuse for a person.
Kuomintang
Kurd
kurgan
Kuwait
kvass
kvetch
Kwa
kwashiorkor
*kweie-
*kwel-
*kwent(h)-