A girl I care about (5)
I believe the answer is:
erica
'a girl' is the definition.
(I've seen this before)
'i care about' is the wordplay.
'about' indicates anagramming the letters.
'i'+'care'='icare'
'icare' with letters rearranged gives 'ERICA'.
(Other definitions for erica that I've seen before include "Moorland plant, girl's name" , "Heath genus; girl's name" , "Plant genus of garden heather" , "ling" , "Girl's name - heather" .)