1. 
[syn: about, almost, most, nearly, near, nigh, virtually, well-nigh]
The Collaborative International Dictionary of English v.0.48:
Well-nigh \Well"-nigh`\, adv.
   Almost; nearly. --Chaucer.
   [1913 Webster]
WordNet (r) 3.0 (2006):
well-nigh
    adv 1: (of actions or states) slightly short of or not quite
           accomplished; all but; "the job is (just) about done";
           "the baby was almost asleep when the alarm sounded";
           "we're almost finished"; "the car all but ran her down";
           "he nearly fainted"; "talked for nigh onto 2 hours"; "the
           recording is well-nigh perfect"; "virtually all the
           parties signed the contract"; "I was near exhausted by
           the run"; "most everyone agrees" [syn: about, almost,
           most, nearly, near, nigh, virtually, well-
           nigh]