Asian with collar up clearing vessel, almost (11)
I believe the answer is:
bangladeshi
'asian' is the definition.
(Bangladeshi is an example)
'collar up clearing vessel almost' is the wordplay.
'collar' becomes 'nab' (both can mean to catch a person).
'up' says the letters should be written in reverse (in down clue: letters go upwards).
'clearing' becomes 'glade' (synonyms).
'vessel almost' becomes 'shi' (I can't explain this - if you can you should give a lot more credence to this answer).
'nab' back-to-front is 'ban'.
'ban'+'glade'+'shi'='BANGLADESHI'
'with' acts as a link.
Can you help me to learn more?
(Other definitions for bangladeshi that I've seen before include "Foreigner" , "Native of Dhaka" , "From Dhaka, perhaps" , "from South Asian republic" .)