Lavished affection on a boy at a party (5)
I believe the answer is:
doted
'lavished affection' is the definition.
(I've seen this before)
'boy at a party' is the wordplay.
I cannot quite see how this works, but
'boy' could be 'ted' (short for Edward or Theodore) and 'ted' is located in the answer.
'party' could be 'do' (do can informally mean a party) and 'do' is found within the answer.
No letters remain.
This explanation may well be incorrect...
'on a' is the link.
Can you help me to learn more?
(Other definitions for doted that I've seen before include "Showed (excessive) love" , "- Upon means was foolishly fond of (someone)" , "was foolish" , "Was weakly affectionate" , "Lavished affection" .)