That's peculiar, not even Italy misses Al (6)
I believe the answer is:
oddity
'that's peculiar' is the definition.
(something odd or peculiar)
'not even italy misses al' is the wordplay.
'not even' becomes 'odd' ('odd' is the opposite to 'even').
'misses' suggests deleting specific letters.
'italy' with 'al' taken away is 'ity'.
'odd'+'ity'='ODDITY'
(Other definitions for oddity that I've seen before include "Toy did (anag.)" , "Curious item" , "Something strange or unusual" , "Peculiar thing or person" , "Twelve months" .)