Love pretentiousness? No thanks (9)
I believe the answer is:
affection
'love' is the definition.
(I know that love can be written as affection)
'pretentiousness? no thanks' is the wordplay.
'pretentiousness?' becomes 'affectation'.
'no' suggests deleting specific letters.
'thanks' becomes 'ta' (UK informal version of 'thank you').
'affectation' with 'ta' taken away is 'AFFECTION'.
(Other definitions for affection that I've seen before include "Fondness or liking" , "Fond attachment" , "Goodwill" , "Warm regard" , "Feeling of fondness" .)