sheepish
Feeling mildly embarrassed or foolish after a small mistake.
Sheepish means feeling or looking embarrassed or foolish because you've done something awkward, wrong, or silly. When you accidentally call your teacher “Mom” in class and everyone laughs, that hot-faced, slightly ashamed feeling is sheepishness. You might give a sheepish grin when you realize you've been wearing your shirt inside out all day.
The word suggests a particular kind of embarrassment: not the crushing shame of doing something truly terrible, but the mild, awkward discomfort of a small mistake or silly moment. A student caught passing notes might offer a sheepish smile to the teacher. Someone who forgot their best friend's birthday might show up with a sheepish apology and a hastily bought card.
Sheepish is usually paired with words like grin, smile, or look. You might feel sheepish when you realize you've been arguing passionately for the wrong answer, or when you trip over your own feet in front of a crowd. It's that universal “oops” feeling we all know too well.