Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
undoer is a noun meaning "a seducer who ruins a woman". It carries 3 recorded senses.
a person who unfastens or unwraps or opens
“children are talented undoers of their shoelaces”
a person who destroys or ruins or lays waste to
“a destroyer of the environment”
“jealousy was his undoer”
“uprooters of gravestones”
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for undoer come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.