Give the kid a quid, that's all (5)
I believe the answer is:
total
'all' is the definition.
(thesaurus)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for total that I've seen before include "Absolute; sum" , "Ruin" , "French oil and gas company" , "Final tally" , "It might be grand" .)