Rare fright catching cold (6)
I believe the answer is:
scarce
'rare' is the definition.
(similar in meaning)
'fright catching cold' is the wordplay.
'fright' becomes 'scare' (synonyms).
'catching' means one lot of letters goes inside another.
'cold' becomes 'c' (eg on taps).
'scare' placed around 'c' is 'SCARCE'.
(Other definitions for scarce that I've seen before include "Not enough to meet demand" , "Rarely seen" , "Not plentiful, in short supply" , "Few and far between" , "Hardly" .)