What do indifference mean?

lack of interest, concern, or sympathy.

"she shrugged, feigning indifference"

synonyms: lack of concern, unconcern, disinterest, lack of interest, lack of enthusiasm, apathy, nonchalance, insouciance; More boredom, unresponsiveness, impassivity, dispassion, detachment, coolness "his apparent indifference infuriated her"