Girl with zeal’s first to give canal name (4)
I believe the answer is:
suez
'canal name' is the definition.
(the Suez Canal in Egypt)
'girl with zeal's first' is the wordplay.
'girl' becomes 'sue' ().
'with' is a charade indicator (letters next to each other).
'zeal's first' becomes 'z' (sst letter of 'zeal').
'sue'+'z'='SUEZ'
'to give' is the link.
(Other definitions for suez that I've seen before include "Canal zone" , "Nineteen Fifty-Six crisis canal" , "Location of Egypt's canal" , "Nineteen fifty six crisis" , "International canal" .)