Yankee lied about surrender (5)
I believe the answer is:
yield
'surrender' is the definition.
(yield can mean to give up or surrender)
'yankee lied about' is the wordplay.
'yankee' becomes 'Y' (phonetic alphabet: alpha, bravo, charlie etc.).
'about' indicates anagramming the letters.
'lied' with letters rearranged gives 'ield'.
'y'+'ield'='YIELD'
(Other definitions for yield that I've seen before include "Produce, generate" , "profits" , "Profit" , "Succumb" , "Cede, give way" .)