What Does ISTG Mean?

The abbreviation ISTG is widely used in text messaging and online chat with the meaning "I Swear To God." ISTG is used to add emphasis to a statement (usually a promise, threat, excuse or apology), or as an interjection which expresses surprise, skepticism or exasperation (similar to OMG ("Oh My God!")). For example:
  • Chris: I am going to tell Jon that it was you who sent him the card.
  • Sam: ISTG I will never speak you again if you do!
  • (Here, ISTG is being used to add emphasis to a threat.)
  • Mom: Aunt May is coming to stay over with you while we are away for the weekend.
  • Dani: But mom, that's not necessary! ISTG I won't have anyone round while you're away.
  • Mom: But Dani, ISTG you said the same thing last time, but when we got back the house was trashed and the police were on the doorstep. Mr. Smith is still not talking to us because of what your friends did in his pool!
  • Dani: ISTG that will never happen again. I am a changed girl.
  • (Here, ISTG is being used by Dani to add emphasis to her promises, and by mom as an interjection expressing skepticism.)
  • Aunt May: Dani said he was only going to have one friend over, so I left him alone on Saturday night.
  • Dani's Mom: ISTG, I can't trust anyone to do anything!
  • (Here, ISTG is being used as an interjection, to express exasperation.)
"I Swear to God" represents an oath given before God. It is intended to indicate that the speaker/sender is not being frivolous or dishonest. However, both the statement "I Swear to God" and the abbreviation ISTG are now used so widely with so little thought that both have little consequence.

ISTG is often shortened to S2G ("Swear to God).

Video Summarizing ISTG

Here is a short video explaining this entry on ISTG:

Image for ISTG

When I write ISTG, I mean this: meaning of ISTG ISTG adds emphasis or is used as an interjection.

Summary of Key Points

"I Swear To God" is the most common definition for ISTG on Snapchat, WhatsApp, Facebook, Twitter, Instagram, and TikTok.
Definition:I Swear To God
3: Guessable
Typical Users:
Adults and Teenagers


An Academic Look at ISTG

ISTG is classified as an initialism abbreviation because it is pronounced using its individual letters (i.e., "Eye Tee Ess Gee"). Initialisms are different to acronyms, which are spoken like words.

ISTG is often used as an interjection. Interjections are words used to express feeling or sudden emotion. They can be standalone or as part of a sentence (usually at the start). An interjection can end in an exclamation mark to express a strong feeling or emotion (i.e., it can be written ISTG or ISTG!). However, in the interests of brevity, exclamation marks are often left out of text-based conversations.

Example of ISTG Used in a Text


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