Infrequent
'infrequent' is the definition.
(similar in meaning)
This is the entire clue.
(Other definitions for rare that I've seen before include "Exceptional" , "Exceptionable" , "Not often seen - underdone" , "Seldom encountered" , "thin on the ground" .)
'infrequent' is the definition.
(similar in meaning)
This is all the clue.
(Other definitions for occasional that I've seen before include "Occurring infrequently" , "Irregularly occurring" , "Rare" , "Periodic" , "Happening now and again" .)