Pound — to book takes some time (5)
I believe the answer is:
throb
'pound' is the definition.
(synonyms)
'to book takes some time' is the wordplay.
'book' becomes 'b'.
'takes' means one lot of letters goes inside another.
'some time' becomes 'hr' (I've seen this in other clues).
'to'+'b'='tob'
'tob' going around 'hr' is 'THROB'.
(Other definitions for throb that I've seen before include "Drum" , "Martin -; Kingsley -" , "Strong regular beat" , "Have strong or irregular heartbeat" , "Pulsate with force" .)