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The acronym for it's Still Yo Mother Fuckin' Set.

A term used bodybuilders and weightlifters alike indicating you have not completed a repetition for a particular workout.
Guy 1: My girl just called. I gotta be outta here.

Guy 2: You cannot leave just yet. ISYMFS
by jasonthecancer March 09, 2014
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Jul 26 Word of the Day
Noun: a friend who is usually only called upon by a friend when a more primary/prominent friend is unavailable.

Taken from the term “second string” in an athletic competition situation. In football, if the star quarterback gets injured during a play, the second string is called off the bench to replace him/her. A “Second String Friend” is essentially benched until needed, if ever.

Synonyms: Plan B, Second Choice, Secondary Friend, Benched Until Needed
I got a call from X the other night. She had an extra ticket to a concert she bought for a friend, but they couldn’t make it so she called me to ask if I wanted to go because I am her Second String Friend.
by Deus-ex-machina August 26, 2020
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2
The acronym for I Suck Your Mother's Fingers Slowly.

Term used by MILF lovers and feet fetishists. Often tattooed on different body parts to inform cougars about your preferences.
Woman: Hey is that ISYMFS on Your arm?
Boy: Yes it is.
Woman: Let's go to my house and talk about it.
by MichealQA August 13, 2019
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