reckless

• rechless, retchless (obsolete)

From Middle English rekles, reckeles, rekkeles, (also recheles), from Old English rēcelēas (“reckless, careless, negligent”), equivalent to reck +‎ -less. Cognate with West Frisian roekeleas (“reckless”), Dutch roekeloos (“reckless”), German Low German ruuklos (“careless”), German ruchlos (“careless, notorious”).

reckless (comparative recklesser or more reckless, superlative recklessest or most reckless)

1. Careless or heedless; headstrong or rash.
2. Indifferent to danger or the consequences.
   • 2018 July 25, A. A. Dowd, “Fallout may be the Most Breathlessly Intense Mission: Impossible Adventure Yet”, in The A.V. Club‎, archived from the original on 31 July 2018:

     Escalation is the film’s nuclear energy source. It’s there, of course, in the downright lunatic stunts performed by [Tom] Cruise, again defying good sense and his own advancing years to top his previous feats of reckless self-endangerment.

• reckful

• recklessness

• clerkess