This is how you sign Armpit in American Sign Language.

How to sign

To sign "Armpit" in American Sign Language(ASL), gently elevate your non-dominant arm and, with the index finger of your dominant hand, trace an arc to indicate the hollow of your armpit.

To sign "Armpit" in American Sign Language (ASL), raise your non-dominant arm slightly and use the index finger of your dominant hand to draw an arc that represents the hollow of your armpit.