His behavior was unsuitable for the occasion.

I feel unsure about my decision.

He is an untalented musician.

The scientist conducted the experiment, knowing full well the unthinkably high stakes involved.

She carefully untied the knot.

He gave unto them the gift of knowledge.

The untreated wood is susceptible to damage from insects and weather.

The cottage garden overflowed with vibrant blooms, untrimmed and unruly but bursting with life.

The unusualness of the situation made everyone feel uncomfortable.

She was unwilling to go to the party.