Wager with little Elizabeth (3)
I believe the answer is:
bet
'wager' is the definition.
(synonyms)
'with little elizabeth' is the wordplay.
'with' says the answer is hidden in the clue.
'BET' can be found hidden inside 'little elizabeth'.
(Other definitions for bet that I've seen before include "Wager, or the sum waged" , "Speculation" , "22 across will accept one" , "Wager, speculate" , "Money risked on a gamble" .)