Yeah, not precisely a trope question, but I don't know where this goes...

On the Hyper Awareness trope, it says " she has a "tell" that is a slight shaking of her left foot.".

Neither dictionaries nor google were kind enough to serve me the meaning of "tell" in this context.

So what the heck is that? A secret sign? A personal mark? Something completely different?

Thanks for your answer. And maybe, while you're at it, you might want to replace the word with something your regular non-native-speaking joe (i.e., me) can understand. ;-)

In that case, used in the sense of poker, though it can be applied in other contexts.

A "tell" is something like a nervous tic. Something you do with your body, usually something you're not aware of, when you're in a tense or stressful situation.

To put it simply: every human being on the planet has a pattern whenever they do a certain activity or feel a certain emotion. We're creatures of habit, so we tend to do everything in a sequence. Everything.

A person who is good at deciphering body language can figure out these patterns, both on a social and personal scale. For example, when women are interested in someone sexually, they typically arch their backs, touch parts of their body or move their wrists limply. That's a social "tell". A personal tell is something like a finger that twitches whenever you tell a lie, or moving a foot one centimeter before throwing a punch.

And there's no way to completely eliminate them—they're always there, no matter how subtle. Even covering up a tell just creates another.

To be even more specific, people have specific tells to show that they're hiding something. In some cases, that tell can be even more obvious than what you're trying to hide in the first place. It's always possible to read someone... it's just much easier for those with Hyper Awareness.

Tell in this context means a subconscious, unintended physical cue of an emotion.

A behavior that tells you something about what the person is thinking. Often idiosyncratic, so you may have to learn a person's tells to beat them at poker, but there are some fairly common tells shared by lots of people. Blushing would be an obvious example.

I'm amazed that none of the quick on-line dictionaries I checked had the noun form. It's not like it's a new coinage or something. It probably goes back to the 1800s among poker players, and is also a common term among stage magicians. Probably popular in cop shops too, or anywhere where you have to try to read people. You really shouldn't need an OED for a term this common.

Wait...

(checks dictionaries)

Wow, @7 is correct. It isn't in many online dictionaries, and I know the term is at least 15 years old (based on when I first heard it used in that context), and I have little reason to doubt that it was used as such in the 1800s.

I can't check my Door Stopper, 2000-page dictionary until later, but the desk dictionary I have doesn't list this at all. I searched through several online dictionaries, and only the Oxford Dictionaries have it listed as an unconscious action to hint at the truth.

To be fair, said dictionary isn't exactly new. I have one published in the last 12 months in addition to the Door Stopper at home. I'll have to check that later. Still, I imagine that the page in question looks a bit obtuse to those not familiar with said usage at all. Especially if English isn't your first language.