transitive verb undertook -·took′, undertaken -·tak′en, undertaking -·tak′·ing

1. to take upon oneself; agree to do; enter into or upon (a task, journey, etc.)
2. to give a promise or pledge that; contract he undertook to be their guide
3. to promise; guarantee
4. to make oneself responsible for; take over as a charge

Etymology: ME undertaken: see under- & take

intransitive verb

1. Archaic to take on responsibility, pledge oneself, guarantee, or be surety (for)
2. ☆ Informal to work as an undertaker (sense )