Following behind, expressing hesitation? (5)
I believe the answer is:
after
'following behind' is the definition.
(I've seen this in another clue)
'expressing hesitation?' is the wordplay.
'expressing' becomes 'aft' (I can't explain this - if you can you should give a lot more credence to this answer).
'hesitation?' becomes 'er' (sound made while hesitating - um, er).
'aft'+'er'='AFTER'
Can you help me to learn more?
(Other definitions for after that I've seen before include "In pursuit of, behind" , "Behind; in quest of" , "At a later time or behind" , "Coming later in time" , "since" .)