Cross with Leo, perhaps (4,4)
I believe the answer is:
plus sign
'cross' is the definition.
(I've seen this before)
'with leo perhaps' is the wordplay.
'with' becomes 'plus'.
'leo perhaps' becomes 'sign' (leo is a kind of sign).
'plus'+'sign'='PLUS SIGN'
(Other definitions for plus sign that I've seen before include "(4,4)" , "//www.crosswordgiant.com/crossword-clue/1252911/" , "cross" .)