Definition of "miffed"

I was miffed at Rick for his behavior. I was miffed at the coach, not for his naivete of deafness, but for his arrogance, which converted his ignorance to stupidity.

2003, Jim Brewington, Let There Be Light Please!, page 130

And also, it's generally not a good idea to prank someone who's already miffed at you.

2018, Josh Scorcher, Taking "28 Pranks Later" too Seriously

Donors might be miffed to find that a magnificent gift was not earmarked for rescue.

2021 November 27, “In preparing for disasters, museums face tough choices”, in The Economist‎