To make a romantic or sexual advance to; to hit on.(verb)
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Use "come on to" in a sentence
"The speaker whom he addressed was our sometime friend Marks, who, with that valuable perservance which characterized him, had come on to Sandusky, seeking whom he might devour."
"He knew she was in love with Graham Peters, but yet, he was trying to come on to her."
"And so he came back, and brought back the people on foot; and these three fine strokes he made in the sight of the Lord of Ashur and the rich men in Acre, and in the sight of all the women who had come on to the walls to see the Saracens."