Number observed, outside of five (5)
I believe the answer is:
seven
'number observed outside of five' is the definition.
'seven' can be an answer for 'number' (I've seen this before). I'm not certain of the 'observed outside of five' bit.
'number observed outside' is the wordplay.
'number' becomes 'v' (V is an example).
'observed' becomes 'seen' (synonyms).
'outside' indicates putting letters inside.
'v' placed inside 'seen' is 'SEVEN'.
Can you help me to learn more?
(Other definitions for seven that I've seen before include "Wonders of the World - Deadly Sins" , "Cube root of 343" , "Numeral" , "VII" , "equivalent of uproar [7D]" .)