Dirigible excellent? A tear? Keeping quiet (7)
I believe the answer is:
airship
'dirigible' is the definition.
(synonyms)
'excellent? a tear? keeping quiet' is the wordplay.
'excellent?' becomes 'ai' (resembles 'A1', old-fashioned term for excellent).
'a tear?' becomes 'rip' (rip is a kind of tear).
'keeping' means one lot of letters goes inside another (some letters kept inside).
'quiet' becomes 'sh' ('sh' is used to tell someone to be quiet).
'rip' enclosing 'sh' is 'rship'.
'ai'+'rship'='AIRSHIP'
(Other definitions for airship that I've seen before include "Means of transport" , "High-flyer" , "Lighter-than-air craft" , "need approval from CAA" , "flying craft" .)