Keep away from a vacuum (5)
I believe the answer is:
avoid
'keep away' is the definition.
(I've seen this in another clue)
'a vacuum' is the wordplay.
'vacuum' becomes 'void' (I've seen this in another clue).
'a'+'void'='AVOID'
'from' is the link.
(Other definitions for avoid that I've seen before include "Eschew" , "Desist" , "Shy away from" , "Steer clear of, dodge" , "Miss" .)