tail-off noun 1tail off verb 1forms 4 noun1 •A gradual diminution. tail off verb1 •To gradually subside or diminish.After losing to Sam Querrey in the third round of Wimbledon in 2016, Djokovic alluded to difficulties in his personal life and his form subsequently tailed off. — 2018 formstailed off · tailing off · tails off · tail-offs