Significance of pause in speech (6)
I believe the answer is:
weight
'significance' is the definition.
(I've seen this before)
'pause in speech' is the wordplay.
'pause' becomes 'wait' (wait is a kind of pause).
'in speech' indicates a 'sounds like' (homophone) clue.
'wait' is a homophone of 'WEIGHT'.
'of' acts as a link.
(Other definitions for weight that I've seen before include "Attach importance to" , "Importance, oppressive force" , "Gravitational pull" , "Trouble" , "Vertical force exerted by a mass" .)