armpit

American  

[ahrm-pit] / ˈɑrmˌpɪt /

noun

1. the hollow under the arm at the shoulder; axilla.

2. Slang. the worst possible place or area.

   Their car has broken down, stranding them in the armpit of California until it can be fixed.

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armpit British  

/ ˈɑːmˌpɪt /

noun

1. Technical name: axilla.  the small depression beneath the arm where it joins the shoulder

2. slang an extremely unpleasant place

   the armpit of the Mediterranean

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Etymology

Origin of armpit

First recorded in 1300–50; Middle English; arm ¹ + pit ¹ ( def. )

Explanation

Your armpit is the area underneath your upper arm, where it connects to your shoulder. Armpits tend to be smelly, so we would advise to steer clear of an open armpit on a bus or subway. Another common word for armpit is "underarm," while the official anatomical term is axilla. Perhaps because your armpits tend to get sweaty and a little smelly after you exercise, the word armpit is sometimes used as a derogatory term for an unattractive place: "That city is so ugly it's the armpit of New Jersey." Before armpit, the axilla was known as an arm-hole.

Example Sentences

Eve Ross, who is a nursery worker in Kent, went to her doctor after she discovered a small lump in her armpit in January 2024.

From BBC • Oct. 30, 2025

When Gustave Flaubert saw Antonio Canova’s sculpture “Eros and Psyche” in 1845, he surreptitiously kissed Psyche’s marble armpit.

From The Wall Street Journal • Oct. 24, 2025

The white tee doesn’t sit the same way, or inevitably accumulates a yellowish stain in the armpit crease.

From Slate • Dec. 28, 2024

And its location in the armpit of the 605 and 210 freeways made it easily accessible from anywhere in the Southland.

From Los Angeles Times • Dec. 23, 2024

I thaw one in my armpit and put it on his foot and we start off.

From "Woodsong" by Gary Paulsen