WordNet (r) 3.0 (2006):

bump into
    v 1: collide violently with an obstacle; "I ran into the
         telephone pole" [syn: run into, bump into, jar
         against, butt against, knock against]

Moby Thesaurus II by Grady Ward, 1.0:

67 Moby Thesaurus words for "bump into":
   alight upon, bang, bang into, blunder upon, bump, cannon, carom,
   carom into, chance upon, clash, collide, come across, come among,
   come into collision, come on, come up against, come upon, concuss,
   confront, confront each other, crack up, crash, crash into, crump,
   crunch, dash into, discover serendipitously, encounter,
   fall across, fall among, fall foul of, fall in with, fall upon,
   foul, happen upon, hit, hit against, hit upon, hurt, hurtle,
   impinge, knock, knock against, light upon, meet, meet head-on,
   meet up with, meet with, percuss, pitch upon, run across, run into,
   run smack into, run up against, run upon, sideswipe, slam into,
   smack into, smash, smash into, smash up, strike, strike against,
   stumble on, stumble upon, tumble on, whomp