With great speed (7)
'with great speed' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for rapidly that I've seen before include "Quickly" , "right off the bat" , "Speedily" , "At a great rate" , "Fast" .)
'with great speed' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for amain that I've seen before include "showing great strength in poetry" , "at great speed" , "at full speed" , "violently" , "in great haste" .)