Cancels practically recent openings (7)
I believe the answer is:
negates
'cancels' is the definition.
(I've seen this before)
'practically recent openings' is the wordplay.
'practically' means to remove the last letter.
'recent' becomes 'new' (similar in meaning).
'openings' becomes 'gates' (I've seen this in another clue).
'new' with its last letter taken away is 'ne'.
'ne'+'gates'='NEGATES'
(Other definitions for negates that I've seen before include "Counteracts" , "Repudiates" , "Nullifies" , "Denies the truth of" , "Cancels" .)