Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
well-nigh is an adverb meaning "(of actions or states) slightly short of or not quite accomplished; all but". It carries one recorded sense.
(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”
Definitions, synonyms and semantic relations for well-nigh come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.