Wayward word uttered by hopeful setting out to claim love? (4,2,3,6)
I believe the answer is:
slip of the tongue
'wayward word uttered' is the definition.
(something said by accident)
'hopeful setting out to claim love?' is the wordplay.
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'to claim' is an insertion indicator.
'love?' becomes 'o' (In tennis, 'love' means 'zero').
'hopeful'+'setting'='hopefulsetting'
'hopefulsetting' anagrammed gives 'slipofthetngue'.
'slipofthetngue' placed around 'o' is 'SLIP OF THE TONGUE'.
'by' is the link.
(Other definitions for slip of the tongue that I've seen before include "Error in words" , "a small error" , "mistake one hears" , "vocal error" .)