come on1
1(Of a state or condition) start to arrive or happen: she felt a mild case of the sniffles coming on [with infinitive]: it was coming on to rain...
- The condition, which came on gradually from the age of ten, also affects Victoria's speech.
- The condition, which came on gradually from when she was 10, also affects her speech.
- It was a condition that had been coming on for years.
2 (also come upon) Meet or find by chance: I came on a station that was playing upbeat songs...
- It might be that you know from the literature that there are specific employers or companies attending that you want to meet with, or you might just come upon them by chance as you wander around.
- So the courtiers arranged for the emperor to take a walk in his park, where he ‘chanced’ to come upon a ‘wandering’ giraffe.
- By chance they come upon her in her hide-out.
3 [in imperative] Said when encouraging someone to do something or to hurry up or when one feels that someone is wrong or foolish: Come on! We must hurry!...
- Police encouraging her to come on, keep running, keep running to them.
- ‘Well, come on,’ encouraged Matt, smiling suspiciously as if he knew something the others didn't.
- That's why I like you, you will always tell me to come on and hurry up with a review!
See parent entry: come
come-on2 
noun informal
1A gesture or remark that is intended to attract someone sexually: she was giving me the come-on...
- Our introduction to Catherine, her frail beauty and desperately clingy sexual come-ons to Wolf, only intensifies our sense that something's desperately wrong at the chateau.
- If he really doesn't want to receive bawdy come-ons, he has ways of stopping it that he should have exercised a LOOOOOOONG time ago.
- I also told him that I needed to be touched and hugged and that I would accept the come-ons from other men.
1.1A marketing ploy, such as a free or cheap offer: the ad was a come-on to try to sell callers other items...
- Part grassroots recruiting strategy and part Tupperware-style marketing, the come-on offers an unusual perk.
- The credit industry's sleazy come-ons, onerous interest rates and frantic marketing to teenagers go unaddressed by Congress; it is only consumers who are expected to be conscientious.
- And come-ons ranging from free digital cameras to $100 mail-in rebates have become the norm.