Classifies as seconds - there's a hole right inside (5)
I believe the answer is:
sorts
'classifies' is the definition.
('sort' can be a synonym of 'classify')
'seconds there's a hole right inside' is the wordplay.
'seconds' becomes 'ss' (an abbreviation for seconds written twice).
'there's a hole' becomes 'O' (O looks like a hole).
'right' becomes 'rt' (abbreviation as in Rt Hon- the Right Honourable).
'inside' means one lot of letters goes inside another.
'o'+'rt'='ort'
'ss' placed around 'ort' is 'SORTS'.
'as' is the link.
(Other definitions for sorts that I've seen before include "classes" , "Categories" , "Systematically arranges" , "Types" , "Arranges in different groups" .)