A flirty tease. A smiling, attractive, eyelash-batting flirty tease, but not necessarily of easy virtue. I have heard "coqueta" used in Mexico in describing very young girls anywhere from a year old to old ladies in their nineties. "¡Ay! Mirala, que coqueta." It's all in the tone of voice and context.

There are many words that do not translate exactly from one language to another or even from one country to another that both speak the *same language, ie Mexico and Spain. The cultures are different and what one culture may be able to indicate with one word and a lift of the brow or inflection of voice might take a paragraph of descriptive writing in another just to give a vague idea of what that one word means. ¡Que vive la diferencia!