Tense cabinet maker breaking spectacles on route to the highest level (7)
I believe the answer is:
topmost
'the highest level' is the definition.
Both the answer and definition are adjectives. Maybe you can see a link between them that I don't see?
'tense cabinet maker breaking spectacles on route' is the wordplay.
'tense' becomes 't' (grammatical abbreviation).
'cabinet maker breaking' becomes 'pm' (I can't justify this - if you can you should believe this answer much more).
'spectacles' becomes 'oo' (OO resembles a pair of glasses).
'on' indicates putting letters inside (as in clothing 'on' a person).
'route' becomes 'st' (abbreviation for street).
'pm' put into 'oo' is 'opmo'.
't'+'opmo'+'st'='TOPMOST'
'to' is the link.
Can you help me to learn more?
(Other definitions for topmost that I've seen before include "Highest" , "Supreme" .)