Piece still lacking odd bits, in the event (6)
I believe the answer is:
castle
'piece' is the definition.
(castle is a kind of piece)
'still lacking odd bits in the event' is the wordplay.
'lacking odd bits' indicates alternate letters (letters in odd-numbered positions removed).
'in' means one lot of letters goes inside another.
'the event' becomes 'case' (synonyms).
The alternating letters of 'still' are 'tl'.
'tl' put inside 'case' is 'CASTLE'.
(Other definitions for castle that I've seen before include "Fortified stronghold" , "Large fortified building" , "Rook, on chess board" , "secure place" , "Make chess move involving king and rook" .)