c. 1600, "assault, assail, begin hostilities against," from French attaquer (16c.), from Florentine Italian attaccare (battaglia) "join (battle)," thus the word is a doublet of attach, which was used 15c.-17c. also in the sense now reserved to attack. Meaning "endeavor to bring into discredit by writing, proposals, etc." is from 1640s. General sense of "begin action" is from 1670s, originally of diseases. Related: Attacked; attacking.
1660s, "violent onset, a falling on with violence and force," from attack (v.). Meaning "fit of a disease" is from 1811. Compare Middle English attach "a seizure or attack" (of fever), late 14c.