Speed hurriedly round on foot (7)
I believe the answer is:
spondee
'foot' is the definition.
(type of metrical foot in poetry)
'speed hurriedly round on' is the wordplay.
'hurriedly' indicates anagramming the letters (writing too quickly, you might mix up letters).
'round' means one lot of letters goes inside another.
'speed' is an anagram of 'spdee'.
'spdee' going around 'on' is 'SPONDEE'.
(Other definitions for spondee that I've seen before include "Metric foot of two long syllables" , "No speed required for poetic metrical foot" , "bit of verse" .)