A child needs a bit of love, that's all (5)
I believe the answer is:
total
'all' is the definition.
(thesaurus)
'a child needs a bit of love' is the wordplay.
'a child' becomes 'tot' (term for a young child).
'needs' is a charade indicator (letters next to each other).
'bit of' suggests taking the first letters.
The first letter of 'love' is 'l'.
'tot'+'a'+'l'='TOTAL'
'that's' acts as a link.
(Other definitions for total that I've seen before include "final answer" , "given by 8 [ADDING MACHINES]" , "Aggregate amount" , "Comprehensive" , "Whole, complete" .)