Synonyms and related words :
alight upon, blunder upon, bring to bay, bump into, chance upon, close with, come across, come among, come on, come upon, confront, discover serendipitously, encounter, fall across, fall among, fall foul of, fall in with, fall upon, fight hand-to-hand, happen upon, hit upon, light upon, meet, meet head-on, meet up with, meet with, pitch upon, run across, run into, run smack into, run up against, run upon, stumble on, stumble upon, tumble on