Tender name designed to be term of affection (10)
I believe the answer is:
endearment
'be term of affection' is the definition.
(I've seen this before)
'tender name designed' is the wordplay.
'designed' indicates anagramming the letters (designed with the letters).
'tender'+'name'='tendername'
'tendername' anagrammed gives 'ENDEARMENT'.
'to' acts as a link.
(Other definitions for endearment that I've seen before include "Word of affection" , "Pet name" , "Love, affection" , "Expression of love" , "Affectionate term" .)