without so much as a backward glance

IDGAF It's no skin off my nose. It's no skin off my teeth Laodicean absolute disregard airy all the same and hang the cost apathetic apparent disregard arrogant disregard as if I care automaton be all the same to sb be insensible to

الملل واللامبالاة الحياد والانحياز واللامبالاة