An excuse can appear so naive (7)
I believe the answer is:
evasion
'an excuse' is the definition.
(I've seen this before)
'appear so naive' is the wordplay.
'so naive' can be anagrammed to 'EVASION'.
Though, I am not clear how the anagram is indicated.
'can' is the link.
Can you help me to learn more?
(Other definitions for evasion that I've seen before include "The act of dodging the issue." , "prevaricating excuse" , "attempt to withhold truth?" , "Avoidance; equivocation" , "Fencing" .)