Without hesitation think about garden feature (4)
I believe the answer is:
pond
'garden feature' is the definition.
(I've seen this in another clue)
'without hesitation think about' is the wordplay.
'without' indicates named letters should be taken away.
'hesitation' becomes 'er' (sound made while hesitating - um, er).
'think about' becomes 'ponder' (to ponder something is to think about it).
'ponder' with 'er' removed is 'POND'.
(Other definitions for pond that I've seen before include "Small area of still water" , "Pool of still water" , "Small lake" , "Small body of water" , "Himalayan country" .)