Perhaps Caitlin & Ed are twins? (9)
I believe the answer is:
identical
'are twins?' is the definition.
The answer and definition are not the same part of speech. However, adjectives and past participle verbs can sometimes mean the same thing.
'perhaps caitlin ed' is the wordplay.
'perhaps' indicates anagramming the letters.
'caitlin'+'ed'='caitlined'
'caitlined' with letters rearranged gives 'IDENTICAL'.
Can you help me to learn more?
(Other definitions for identical that I've seen before include "Matching" , "Selfsame" , "showing no change" , "Exactly alike, the same in every detail" , "Indistinguishable" .)