Completely tie them in knots, continuously (3,3,4)
I believe the answer is:
all the time
'continuously' is the definition.
(I've seen this before)
'completely tie them in knots' is the wordplay.
'completely' becomes 'all' ('all' can be a synonym of 'completely').
'in knots' is an anagram indicator (I've seen this in other clues).
'tie'+'them'='tiethem'
'tiethem' anagrammed gives 'thetime'.
'all'+'thetime'='ALL THE TIME'
(Other definitions for all the time that I've seen before include "Constantly" , "Without exception" , "Continuously" .)