undertake in WordNet English dictionary

1. enter upon an activity or enterprise
   undertake  set about  attempt 
   
2. enter into a contractual arrangement
   contract  undertake 
   
3. promise to do or accomplish
   "guarantee to free the prisoners"
   undertake  guarantee 
   
4. accept as a challenge
   "I'll tackle this difficult task"
   undertake  tackle  take on 
   
5. accept as a charge
   undertake  take in charge