Impressive eastern prince seen occasionally (4)
I believe the answer is:
epic
'impressive' is the definition.
(I've seen this before)
'eastern prince seen occasionally' is the wordplay.
'eastern' becomes 'e'.
'prince' becomes 'p'.
'seen' means one lot of letters go next to another.
'occasionally' becomes 'ic' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'e'+'p'+'ic'='EPIC'
Can you help me to learn more?
(Other definitions for epic that I've seen before include "Long account" , "A long poem or book with adventurous theme" , "Blown up" , "Long poem etc" , "Tale of heroic deeds" .)