refusenik n.

c. 1300, "reject, spurn, decline" a request, demand, invitation, etc.; also intransitive, "to make refusal;" from Old French refuser "reject, disregard, avoid" (12c.), from Vulgar Latin *refusare, a frequentative verb from the past-participle stem of Latin refundere "give back, restore, return," literally "pour back, flow back," from re- "back" (see re-) + fundere "to pour" (from nasalized form of PIE root *gheu- "to pour").

The intransitive meaning "refuse to do something" is from late 14c.; that of "fail to comply" is from 1520s (originally of horses); that of "repudiate, disown, disavow" is attested from early 15c. but now is obsolete. Nares reports that God refuse me! was "formerly a fashionable imprecation." Related: Refused; refusing. 

O Romeo, Romeo! wherefore art thou Romeo?

Deny thy father and refuse thy name;

as in beatnik, etc., suffix used in word formation from c. 1945, from Yiddish -nik (as in nudnik "a bore"), from Russian -nik, common personal suffix meaning "person or thing associated with or involved in" (compare nudnik; kolkhoznik "member of a kolkhoz"). Rocketed to popularity with sputnik (q.v.), hence its brief vogue in English word-formation, as in robotnik "person behaving with mindless obedience" (1960).