Poker players do so in the canteen (4)
I believe the answer is:
ante
'poker players do' is the definition.
I can't tell whether this definition defines the answer.
'in the canteen' is the wordplay.
'in' says the answer is hidden in the clue.
'ANTE' is hidden within 'canteen'.
'so' acts as a link.
Can you help me to learn more?
(Other definitions for ante that I've seen before include "Poker-player's stake before the deal" , "expected from stake" , "Pay" , "Preceding birth" , "Stake, bet" .)