Close down before time, almost (6)
I believe the answer is:
nearly
'close' is the definition.
(thesaurus)
'down before time almost' is the wordplay.
'down' becomes 'dn'.
'before time' becomes 'early' (I've seen this before).
'almost' means to remove the first letter.
'dn'+'early'='dnearly'
'dnearly' with its first letter taken away is 'NEARLY'.
(Other definitions for nearly that I've seen before include "parsimoniously" , "Noon at eleven fifty nine am" , "Almost, not quite" , "Give out a bright light" , "Close" .)