Staunch supporters finally satisfied, given a lift (4)
I believe the answer is:
'staunch' is the definition.
(I know that staunch can be written as stem)
'supporters finally satisfied given a lift' is the wordplay.
'finally' indicates one should take the final letters.
'satisfied' becomes 'met' (as in 'met the conditions of his contract').
'given a lift' shows that the letters should be reversed in order.
The final letter of 'supporters' is 's'.
'met' backwards is 'tem'.
(Other definitions for stem that I've seen before include "Stop; stalk; ship's timber" , "Block" , "Tube" , "Supporting structure" , "Ski turn and plant support" .)