thoughtlessness vs trait

thoughtlessness and trait both are nouns.

Word	Noun	Adjective	Verb	Adverb
thoughtlessness	Yes	No	No	No
trait	Yes	No	No	No

As nouns, trait is a hypernym of thoughtlessness; that is, trait is a word with a broader meaning than thoughtlessness:

thoughtlessness (noun)	trait (noun)
the trait of not thinking carefully before acting	a distinguishing feature of your personal nature
the quality of failing to be considerate of others