Dashing and reckless -- one king about to be captured (6)
I believe the answer is:
rakish
'dashing' is the definition.
('rakish' can be a synonym of 'dashing')
'reckless one king about to be captured' is the wordplay.
'reckless' becomes 'rash' ('rash' can be a synonym of 'reckless'**).
'one' becomes 'i' (Roman numeral).
'king' becomes 'k'.
'about' indicates an anagram.
'to be captured' is an insertion indicator.
'i'+'k'='ik'
'ik' anagrammed gives 'ki'.
'rash' going around 'ki' is 'RAKISH'.
'and' is the link.
(Other definitions for rakish that I've seen before include "Jaunty; dissolute" , "Marked by unconventionality or disreputableness" , "Jaunty; fast-looking (boat)" , "Given to philandering" , "Dashing, devil-may-care" .)