Dumpy crew eliminating last outsider in tournament (5)
I believe the answer is:
squat
'dumpy' is the definition.
(both can mean short and stocky)
'crew eliminating last outsider in tournament' is the wordplay.
'crew' becomes 'squad' (I've seen this before).
'eliminating last' means to remove the last letter.
'outsider in' says to take the initial letters (one of the letters on the outside of the word).
The first letter of 'tournament' is 't'.
'squad' with its last letter removed is 'squa'.
'squa'+'t'='SQUAT'
(Other definitions for squat that I've seen before include "Building occupied without permission" , "Illegally occupy property" , "Occupy unlawfully; dumpy" , "Hunker down" , "occupy room?" .)