tuff /tʌf/adjective 1noun 1forms 5 adjective1 •(Internet) Impressive, amazing, awesome, cool.bro thinks he's tuff noun1 •A light porous rock, now especially a rock composed of compacted volcanic ash varying in size from fine sand to coarse gravel.This is what makes an ignimbrite; the general term for this kind of volcaniclastic rock is ‘tuff’. — 2004 formstuffs · more tuff · tuffer · most tuff · tuffest