In a straight line? Amazing cartwheels, if so (2,3,4,5)
I believe the answer is:
as the crow flies
'in a straight line?' is the definition.
(I've seen this before)
'amazing cartwheels if so' is the wordplay.
'amazing' is an anagram indicator.
'cartwheels'+'if'+'so'='cartwheelsifso'
'cartwheelsifso' anagrammed gives 'AS THE CROW FLIES'.
(Other definitions for as the crow flies that I've seen before include "taking shortest route" , "move in a straight line" , "By direct route" , "without deviating" , "How rook moves" .)