You’re cursi when you want to sound romantic, but you end up saying something embarrassing and awkward.
Basically it’s anything that is a cliche to the point of becoming awkward, not cool or very annoying. but this is not the whole meaning of cursi.
Cursi is something or someone that sounds stereotypically sentimental, like a romantic line of those you hear in movies over and over again, like: “For you the sun and moon would come down.”
In short, what cursi means is an excess of sentimentality, excess of ridiculousness, excess of phrases that are considered cliche and even excess of nonsense. In general, everything cursi is often embarrassing.
And you know the meaning of cursi