Obstacle, as it's windy for server (7)
I believe the answer is:
barista
'server' is the definition.
(I know that barista is a type of server)
'obstacle as it's windy' is the wordplay.
'obstacle' becomes 'bar' (bar can mean an obstacle or blockage).
'windy' indicates anagramming the letters (windy suggests disruption).
'as'+'it'='asit'
'asit' with letters rearranged gives 'ista'.
'bar'+'ista'='BARISTA'
'for' is the link.
(Other definitions for barista that I've seen before include "Arabist (anag)" , "Coffee bar server" , "coffee-maker" , "Coffee servitor" , "Starbucks employee" .)