It gives one pause, particularly in this clue (5)
I believe the answer is:
comma
'it gives one pause' is the definition.
(I've seen this in another clue)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for comma that I've seen before include "Punctuation mark indicating slight pause" , "repeatedly found in lists" , "part of list, invariably" , "Puncuation mark" , "Punctuation mark - butterfly" .)