Verb
be on to (third-person singular simple present is on to, present participle being on to, simple past was on to, past participle been on to)
(idiomatic) To figure out; to realize the truth.
I was planning it as a surprise, but I think he is on to me.
But when Jessica meets the entire unhappy family at the debut show of Blake's protégé — a reclusive ex-miner producing gloomy canvases in the Black Mountains of southeast Wales — she starts to wonder whether Elinor might be on to something. Source: Internet
Figure that one out, and you’ll be on to something. Source: Internet
Here, alas, he may be on to something. Source: Internet
I'm almost caught up with my work, and then it'll be on to fabric-y things. Source: Internet
In my house we call this stuff Meatloaf Sauce, but you know, ardubu may be on to something. Source: Internet
Our team will be on to answer any questions you have when integrating your app with Google Drive. Source: Internet