Strange capital with unknown content, not as you would expect (8)
I believe the answer is:
atypical
'content not as you would expect' is the definition.
I can't tell whether this definition defines the answer.
'strange capital with unknown' is the wordplay.
'strange' is an anagram indicator.
'with' is an insertion indicator.
'unknown' becomes 'y' (algebra).
'capital' is an anagram of 'atpical'.
'atpical' placed around 'y' is 'ATYPICAL'.
Can you help me to learn more?
(Other definitions for atypical that I've seen before include "Irregular" , "Not conforming to a norm or average" , "Deviating from what is usual or common" , "Uncharacteristic" , "Nonconforming" .)