Rather concerned with terrible dates (7)
I believe the answer is:
instead
'rather' is the definition.
(I know that rather can be written as instead)
'concerned with terrible dates' is the wordplay.
'concerned with' becomes 'in' (I've seen this in other clues).
'terrible' indicates anagramming the letters.
'dates' anagrammed gives 'stead'.
'in'+'stead'='INSTEAD'
(Other definitions for instead that I've seen before include "as an alternative option" , "As a substitute" , "use this as a replacement" , "Alternatively" , "In lieu" .)