IPA: /ˌɪnəˈfɛnsɪvli/
KK: /ɪnəˈfɛnsɪvli/
In a way that does not cause offense or hurt feelings.
She spoke inoffensively, making sure not to upset anyone in the room.
Inoffensively → It is formed from "in-" (meaning not) and "offensive" (from Latin "offensivus", meaning causing offense) and the suffix "-ly" (meaning in a manner). The word "inoffensively" means in a manner that does not cause offense.
Think of 'not' ('in-') causing 'offense' — that's why inoffensively means doing something in a way that doesn't upset others.