King ending in Bangladesh, an Asian ruler (4)
I believe the answer is:
khan
'asian ruler' is the definition.
(I've seen this before)
'king ending in bangladesh an' is the wordplay.
'king' becomes 'k'.
'ending in' suggests the final letters.
The final letter of 'bangladesh' is 'h'.
'k'+'h'+'an'='KHAN'
(Other definitions for khan that I've seen before include "Caravanserai; Asian ruler" , "Persian governor" , "Imran --, cricketer" , "Title given to rulers in Asian countries" , "See 14" .)