✅ Cool refers to someone who is calm and composed (She was surprised by how cool she was under pressure).

✅ Imperturbable refers to someone who isn’t easily excited, upset, or agitated (The imperturbable diplomat ignored the cruel comment).

✅ Cool also suggests being logical and thinking clearly under pressure (If I keep cool, I can come up with an escape plan).

✅ Imperturbable can suggest this but more often suggests being difficult to shock or surprise (No matter what prank we pulled, she was always imperturbable).

✅ Acrid describes something that tastes or smells biting or sharp or that irritates the eyes and nose (Acrid smoke billowed across the sky).

✅ Astringent describes something biting or caustic (The fruit is astringent and not too pleasant to eat).

✅ Although both acrid and astringent describe intense and often irritating tastes and smells, acrid tends to refer to things like smoke and gas, whereas astringent can refer to food or cleaning ingredients, such as vinegar or lemon juice.

✅ Sting means to cause a sharp, irritating pain (The burn started to sting when the water hit it).

✅ Smart means to cause, or feel, a sharp, especially irritating and stinging, pain (His hand smarted where he had accidentally cut it).

✅ Although sting and smart refer to similar types of pain, sting more often refers to a pain caused by something hurting you, whereas smart more often refers to the pain you feel during or after being hurt (The cold rain stung her skin; Her twisted ankle still smarted after a few weeks).