Hasten', in chiefly poetic usage (3)
I believe the answer is:
hie
'hasten'' is the definition.
(synonyms)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for hie that I've seen before include "Go quickly (archaic)" , "Be quick (lit.)" , "Make one's way quickly" , "Hasten" , "make haste" .)