Nothing happening? Close (3,2)
I believe the answer is:
zip up
'close' is the definition.
(thesaurus)
'nothing happening?' is the wordplay.
'nothing' becomes 'zip' (synonyms).
'happening?' becomes 'up' (eg in the phrase 'something's up').
'zip'+'up'='ZIP UP'
(Other definitions for zip up that I've seen before include "Fasten one's trousers perhaps" , "Fasten (eg jacket)" , "stimulate" .)