ISTG
ISTG (abbreviation) means I swear to God; used in messages to stress that something is true or to signal exasperation. Example: “ISTG I sent that email an hour ago.”
How to use ISTG
Learner’s notesIn plain EnglishA texting way of saying "I swear".
Slang, texting and social media only. Some readers find the phrase itself irreverent, so avoid it in professional writing entirely.
ISTG usually opens the sentence, and an ISTG if… construction is a threat or a complaint rather than a real conditional.
Trace the full origin ↓Fill the gap
Can you complete this real example?
_____ I sent that email an hour ago.
Etymology
An initialism of "I swear to God", popularised through texting and social media.