What does ’hot under the collar’ mean?

What does the English idiom ’hot under the collar’ mean? Improve your English vocabulary with this free 3-minute English language tutorial. You’ll find a free downloadable transcript on our website: It’s hot in the studio. The air conditioning isn’t working and temperatures are rising. Soon Rob starts to get a little hot under the collar. But this phrase is about more than just body heat. It has to do with anger and also