Host runs wearing bikini bottom? (6)
I believe the answer is:
throng
'host' is the definition.
(I've seen this before)
'runs wearing bikini bottom?' is the wordplay.
'runs' becomes 'r' (cricket abbreviation).
'wearing' means one lot of letters goes inside another.
'bikini bottom?' becomes 'thong'.
'r' inserted into 'thong' is 'THRONG'.
(Other definitions for throng that I've seen before include "A crowded mass of people" , "Dense crowd" , "Large numbers" , "A large crowd of people" , "Large densely-packed crowd" .)