It may be perfect (5)
I believe the answer is:
tense
'it may be perfect' is the definition.
(I've seen this in another clue)
'it may be' is the wordplay.
'it' becomes ''t' (abbreviation. e.g. in 'tis).
'may be' becomes 'ense' (I can't justify this - if you can you should believe this answer much more).
't'+'ense'='TENSE'
Can you help me to learn more?
(Other definitions for tense that I've seen before include "Anxious, high-strung" , "Future, possibly" , "Future perfect? Could be" , "under stress?" , "Could be present" .)