Yankee cracking clue oddly rejected solution (3)
I believe the answer is:
lye
'solution' is the definition.
(I've seen this before)
'yankee cracking clue oddly rejected' is the wordplay.
'yankee' becomes 'Y' (phonetic alphabet: alpha, bravo, charlie etc.).
'cracking' means one lot of letters goes inside another (inserted letters go into a gap or crack).
'oddly rejected' indicates alternate letters.
The alternating letters of 'clue' are 'le'.
'y' going within 'le' is 'LYE'.
(Other definitions for lye that I've seen before include "Cleansing alkaline fluid" , "Alkali washing solution" , "caustic liquid" , "Strong alkaline solution" , "Strongly alkaline solution for washing or cleansing" .)