Sword man who's rather dashing (5)
I believe the answer is:
blade
'sword' is the definition.
(I know that sword can be written as blade)
'man who's rather dashing' is the wordplay.
I cannot really understand how this works, but
'man' could be 'lad' (I have seen 'Young man' mean 'lad' so perhaps 'man' could also mean 'lad') and 'lad' is found within the answer.
The remaining letters 'be' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for blade that I've seen before include "Young chap, dashing" , "A knife, or a dashing fellow" , "Leaf, of grass, say" , "Cutting edge" , "Flat part of an oar" .)