You yearn for something when you really, really want to have it. The lizard in the picture is yearning for the freedom of being outside.
Feelings and facial expressions from happy to sad and all things in between.
Affection, Aghast, Amusement, Anticipation, Apathy, Beserk, Complacent, Contempt, Courage, Covet, Depressed, Desire, Despair, Disappointment, Dissatisfied, Emotion, Enthusiastic, Euphoria, Fear, Frustration, Glum, Grateful, Grief, Grumpy, Guilt, Hate, Impressed, Irate, Ire, Merry, Miserable, Mournful, Nervous, Pity, Pleasure, Rage, Regret, Romance, Sane, Scowl, Sneer, Snicker, Snigger, Sorrow, Stern (Emotion), Stress, Stressed, Suspicious, Temper, Trust