Indicate what's badly done by half the team (6)
I believe the answer is:
denote
'indicate' is the definition.
(I've seen this in another clue)
'badly done by half the team' is the wordplay.
'badly' is an anagram indicator.
'by' is a charade indicator (letters next to each other).
'half the' suggests halving the letters.
'team' halved is 'te'.
'done' anagrammed gives 'deno'.
'deno'+'te'='DENOTE'
'what's' is the link.
(Other definitions for denote that I've seen before include "Mean or signify" , "Be an indication of" , "show" , "Need to (anag) - indicate" , "Be the sign or symbol of" .)