What does it mean when someone is being a tell tale?

[Singingu]

[Subglacial]

A telltale is a signature sign or indication of something. Hoofprints in the snow are a telltale sign that there are deer in the area. A skunky smell in your kitchen is a telltale sign of a gas leak. Bags under your eyes are a telltale sign that you need sleep.

It's an adjective, though, so it's a weird thing to call somebody. Unless they were comparing you to actual tell-tales used to guage the wind direction on a sail boat? That's also a weird thing to call somebody.

Is it possible you misheard them and they were actually calling you a tattle-tale? That's a childish name for a snitch/rat/informant. Somebody who exposes somebody else's attempt to cover up a crime or misdeed. "I broke my mother's favorite vase, and my brother told my mother. He's a tattle-tale."

There's also "tall tale", which is an unbelievable story. "When I asked my student why he didn't turn his homework in, he told me a tall tale about being robbed by pirates." Also a really weird thing to call somebody though.

EDIT: just before I finished typing this, I read that "telltale" actually is British slang for a tattle-tale. That's probably the answer. I'll leave the rest of I wrote here just in case.

[Ielloz]

When someone is a tall tale they’re a person who exaggerates the story more than what really happened truthfully in a real life situation or fictional story.
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Dictionary helps
https://www.dictionary.com/browse/tall-tale

[Anonymous]

they tell people about everything you do

[Anonymous]

They are lying.

[Anonymous]

Tell tale?