na-adjective, noun which may take the genitive case particle 'no'
arrogant; insolent; overbearing
Describes an attitude or behavior that shows no regard for others, as if other people don't matter. Often used in the phrase 人も無げに to modify a verb.
彼は人も無げに振る舞った。
He behaved arrogantly, as if other people didn't matter.
人も無げな態度をとる。
To take an overbearing attitude.
傲慢 is a more formal and direct word for 'arrogant', while 人も無げ is a descriptive phrase emphasizing disregard for others.
無げ is a suffix meaning 'seeming to lack'; 人も無げ literally means 'seeming to lack people (consideration)'.
From 人 (ひと, 'person') + も (inclusive particle) + 無げ (なげ, 'seeming to lack'). The phrase literally means 'as if there were no people', implying a lack of consideration for others.