Expect caper, confusing it with pea (10)
I believe the answer is:
anticipate
'expect' is the definition.
(anticipating is a kind of expecting)
'caper confusing it with pea' is the wordplay.
'caper' becomes 'antic' (synonyms).
'confusing' indicates anagramming the letters.
'with' means one lot of letters go next to another.
'it' put after 'pea' is 'peait'.
'peait' with letters rearranged gives 'ipate'.
'antic'+'ipate'='ANTICIPATE'
(Other definitions for anticipate that I've seen before include "Expect" , "Bargain for" , "Look forward to" , "Foresee" , "Figure on" .)