"fool, clown," 1540s, perhaps from Italian pazzo "fool," a word of unknown origin. Possibly from Old High German barzjan "to rave" [Klein]. But Buck says pazzo is originally euphemistic, and from Latin patiens "suffering," in medical use, "the patient." The form perhaps eas influenced by folk etymology derivation from patch (n.1), on notion of a fool's patched garb.
"ruse, deception," 1937, from earlier adjectival meaning "assumed, feigned" (1620s), a figurative extension of the verbal phrase on the notion of putting on costumes or disguises. To put on (v.), of clothes, garments, etc., is by early 15c.; see from put (v.) + on (adv.). Hence "clothe, cover, assume as covering" (mid-15c.) and "assume the garb or appearance of" (real or feigned), 1520s. The expression put (someone) on "play a trick on, deceive" (by 1958) seems to be a back-formation from the noun.