IPA: /ɪnˈsoʊʃəblɪ/
KK: /ɪnˈsoʊʃəblɪ/
In a manner that is not sociable or friendly; avoiding social interaction or company.
He insociably sat alone at the party, ignoring the other guests.
Insociably → It is formed from "in-" (meaning not) and "sociable" (from Latin "sociabilis", meaning able to be associated with others). The suffix "-ly" (meaning in a manner) indicates the manner of being not sociable. Thus, "insociably" means in a manner that is not sociable or unfriendly.
Think of 'not' ('in-') being able to be 'associated with others' ('sociable') — that's why insociably means behaving in a way that is unfriendly.