wear (one's) heart on (one's) sleeve

To openly display or make known one's emotions or sentiments. My father was always very closed off regarding his feelings, so when I had kids, I made a point of wearing my heart on my sleeve with them. The senator has begun wearing his heart on his sleeve now that he's not seeking re-election.

Fig. to display one's feelings openly and habitually, rather than keep them private. John always has his heart on his sleeve so that everyone knows how he feels. Because she wears her heart on her sleeve, it's easy to hurt her feelings.

Also, pin one's heart on one's sleeve. Openly show one's feelings, especially amorous ones. For example, You can't help but see how he feels about her; he wears his heart on his sleeve. This expression alludes to the former custom of tying a woman's favor to her lover's sleeve, thereby announcing their attachment. Shakespeare had it in Othello (1:1): "But I will wear my heart upon my sleeve for daws to peck at."

If you wear your heart on your sleeve, your feelings are obvious to everyone around you. Note: The heart is traditionally regarded as the centre of the emotions. She's one of these people who wears her heart on her sleeve. She simply doesn't wear her heart on her sleeve so it's sometimes difficult to know what she's feeling. Note: You can also use heart-on-your-sleeve or heart-on-the-sleeve before nouns. You would have thought the heart-on-the-sleeve atmosphere would have suited his nature.

To show one's feelings clearly and openly by one's behavior.

Reveal your emotions so that they are subject to the comments of others. A young man who has a crush on a young lady may tell everyone that he can't live without her, even though his words may be met by his friends' sneers and jeers. If so, he's wearing his heart on his sleeve, which is to say exposing it in a vulnerable place. The phrase comes from Othello, where devious Iago says, For when my outward action doth demonstrate The native act and figure of my heart In compliment extern, 'tis not long after But I will wear my heart upon my sleeve For daws [ravens] to peck at. I am not what I am.