IPA: /ʌnˈseɪfli/
KK: /ʌnˈseɪfli/
In a manner that does not ensure safety; acting or doing something without taking necessary precautions.
He drove unsafely on the icy roads, putting everyone at risk.
Unsafely → It is formed from "un-" (meaning not) and "safe" (from Old French *sauf*, meaning free from danger) and "-ly" (meaning in a manner). The word "unsafely" means in a manner that is not safe or free from danger.
Think of 'not' ('un-') being added to 'safe' to remember that 'unsafely' means in a way that is not safe.