Crowd booting out king? This shows a lot of cheek (5)
I believe the answer is:
thong
'this shows a lot of cheek' is the definition.
The definition suggests a singular noun which matches the answer.
'crowd booting out king?' is the wordplay.
'crowd' becomes 'throng' (thronging is a kind of crowding).
'booting out' suggests deleting specific letters.
'king?' becomes 'R' (abbreviation of Latin rex).
'throng' with 'r' taken away is 'THONG'.
Can you help me to learn more?
(Other definitions for thong that I've seen before include "article of clothing" , "Leather strip that forms the flexible part of a whip: excuse for underwear" , "Beachwear item" , "Sandal" , "G-string" .)