It’s superficial, not in tie up (7)
I believe the answer is:
outward
'it's superficial' is the definition.
(associated in meaning)
'not in tie up' is the wordplay.
'not in' becomes 'out' ('out' is the opposite to 'in').
'tie' becomes 'draw' (synonyms).
'up' says the letters should be written backwards (in down clue: letters go upwards).
'draw' reversed gives 'ward'.
'out'+'ward'='OUTWARD'
(Other definitions for outward that I've seen before include "(In the direction of the) exterior" , "Draw out (anag.)" , "Externally facing" , "Ostensible" , "Away from centre" .)