Cowboy is clumsy, scratching bottom with end of lasso (6)
I believe the answer is:
gaucho
'cowboy' is the definition.
(gaucho is a kind of cowboy)
'clumsy scratching bottom with end of lasso' is the wordplay.
'clumsy' becomes 'gauche' (I've seen this before).
'scratching bottom' means to remove the last letter.
'with' says to put letters next to each other.
'end of' says to take the final letters.
The final letter of 'lasso' is 'o'.
'gauche' with its final letter removed is 'gauch'.
'gauch'+'o'='GAUCHO'
'is' is the link.
(Other definitions for gaucho that I've seen before include "Ranch hand" , "Horseman of the Pampas" , "A cough (anag)" , "Surprise attacker" , "Horseman of the S American plains" .)