Joker’s taunt about solver’s initial time (6)
I believe the answer is:
jester
'joker's' is the definition.
(I've seen this before)
'taunt about solver's initial time' is the wordplay.
'taunt' becomes 'jeer' (jeering is a kind of taunting).
'about' indicates putting letters inside.
'initial' suggests taking the first letters.
'time' becomes 't' (abbreviation).
The initial letter of 'solvers' is 's'.
's'+'t'='st'
'jeer' placed around 'st' is 'JESTER'.
(Other definitions for jester that I've seen before include "one entertaining in court" , "Clown employed to entertain a ruler" , "his work's funny" , "Court humorist" , "Court entertainer (with bells on?)" .)