To take upon one's self; to engage in; to enter upon; to take in hand; to begin to perform; to set about; to attempt.
- To take upon oneself; decide or agree to do: undertake a task.
- To pledge or commit oneself: undertake to care for an elderly relative.
- To set about; begin.
- Obsolete To accept combat with.
- Archaic To make oneself responsible. Used with for.