The "NoCap" emote depicts a blue baseball cap with a red prohibition symbol (circle with a diagonal line through it) overlaid on top. This emote is used to indicate that someone is not telling the truth or exaggerating, essentially meaning "that's not true" or "I don't believe you." It's a visual play on the slang term "cap," which in internet and streaming culture means "lie" or "fake." So "no cap" means "no lie" or "truth," but the emote is often used sarcastically to call out perceived dishonesty.
The NoCap emote originated from internet slang where "capping" means lying and "no cap" means "no lie" or "I'm telling the truth." This slang has roots in African American Vernacular English (AAVE) and gained widespread popularity on social media platforms like Twitter and TikTok around 2017-2018 before making its way to Twitch culture. The emote itself appears to be a custom creation that visualizes this concept, becoming popular on third-party emote platforms like 7TV, BTTV (BetterTTV), and FFZ (FrankerFaceZ) around 2019-2020. Unlike some emotes that are based on specific streamers' faces, this one is a symbolic representation of the slang term.
The NoCap emote is typically used in Twitch chat in the following contexts: