WordNet (r) 3.0 (2006):

divagate
    v 1: lose clarity or turn aside especially from the main subject
         of attention or course of argument in writing, thinking, or
         speaking; "She always digresses when telling a story"; "her
         mind wanders"; "Don't digress when you give a lecture"
         [syn: digress, stray, divagate, wander]

Moby Thesaurus II by Grady Ward, 1.0:

86 Moby Thesaurus words for "divagate":
   angle, angle off, bat around, be absent, bear off, bend, bias,
   branch off, bum, change the bearing, count ties, crook, curve,
   daydream, deflect, depart, depart from, detour, deviate, digress,
   divaricate, diverge, dream, drift, err, excurse, fantasy, flit,
   gad, gad about, gallivant, go about, go adrift, go astray,
   go the rounds, go woolgathering, heel, hit the road, hit the trail,
   hobo, jaunt, knock about, knock around, meander, mooch, moon, muse,
   nomadize, oblique, peregrinate, pererrate, pipe-dream, prowl,
   ramble, range, roam, rove, run about, saunter, sheer, shift, skew,
   slue, snake, stargaze, straggle, stray, stroll, sway, swerve, tack,
   traipse, tramp, trend, turn, turn aside, twist, twist and turn,
   vagabond, vagabondize, vary, veer, walk the tracks, wander,
   wayfare, wind