“Wearing Heart on Sleeve”. This is an interesting expression: “He wears his heart on his sleeve”. That sure is a funny image. I can’t imagine someone actually wearing his heart on his sleeve (sleeve being that part of a shirt that covers your arm).
Of course, it this expression does not mean that someone takes out his heart and attaches it to his sleeve :). What is does refer to, however, is someone who lets everyone know how he or she is feeling, pretty much at any time. For example if your friend just got dumped (i.e. broken up with, relationship over) and he just looks sad all the time, you can say, “yeah, he wears his heart on his sleeve.” As another example, your co-worker often will start crying when she talks about her past love-life, or her family, “she wears her heart on her sleeve.” This expression usually refers to sad emotions as opposed to angry, happy or other emotions.
Oliver, LiveEnglishClass.com Teaching Director