experiencing or marked by or causing sadness or sorrow or discontent; "unhappy over her departure"; "unhappy with her raise"; "after the argument they lapsed into an unhappy silence"; "had an unhappy time at school"; "the unhappy (or sad) news"; "he looks so sad"
a hemoprotein composed of globin and heme that gives red blood cells their characteristic color; function primarily to transport oxygen from the lungs to the body tissues; "fish have simpler hemoglobin than mammals"
capable or worthy of being perceived; "noticeable shadows under her eyes"; "noticeable for its vivid historical background"; "a noticeable lack of friendliness"