Oblique impact from tip of whirling weapon (6)
I believe the answer is:
glance
'oblique impact' is the definition.
(I've seen this before)
'tip of whirling weapon' is the wordplay.
'tip of' indicates one should take the final letters.
'weapon' becomes 'lance' (lance is a kind of weapon).
The last letter of 'whirling' is 'g'.
'g'+'lance'='GLANCE'
'from' is the link.
(Other definitions for glance that I've seen before include "A brief or casual look" , "Butcher's" , "deflection" , "Stroke - gander" , "Take a brief or hurried look" .)