Irritation

ir·ri·ta·tion - a : the act of irritating b : something that irritates c : the state of being irritated2 : a condition of irritability , soreness, roughness, or inflammation of a bodily part


The opposite of irritation


Alone - Etymology: Middle English, from al all + one one1 : separated from others : ISOLATED2 : exclusive of anyone or anything else : ONLY3 a : considered without reference to any other b : INCOMPARABLE, UNIQUE - alone·ness /-'lOn-n&s/ nounsynonyms ALONE, SOLITARY, LONELY, LONESOME, LONE, FORLORN, DESOLATE mean isolated from others. ALONE stresses the objective fact of being by oneself with slighter notion of emotional involvement than most of the remaining terms . SOLITARY may indicate isolation as a chosen course but more often it suggests sadness and a sense of loss . LONELY adds to SOLITARY a suggestion of longing for companionship . LONESOME heightens the suggestion of sadness and poignancy . LONE may replace LONELY or LONESOME but typically is as objective as ALONE . FORLORN stresses dejection, woe, and listlessness at separation from one held dear . DESOLATE implies inconsolable grief at loss or bereavement .

In my opinion Merriam-Webster is wrong, alone and lonely are two very different things.