gaff (n.1) Look up gaff at
"iron hook," c.1300, gaffe, from Old French gaffe "boat hook" (see gaffe). Specifically of the hook on a fishing spear from 1650s.
gaff (n.2) Look up gaff at
"loud, rude talk," 1825, from Scottish dialect, perhaps a survival of Old English gafspræc "blasphemous or ribald speech," or from gaff (n.1) "spear-hook" (see gaffe).
gaff (n.3) Look up gaff at
"cheap music hall or theater; place of amusement for the lowest classes," 1850s, British slang, earlier "a fair" (1753), of unknown origin.