Wordnet 3.0
NOUN (2)
1. 
 a custodian who is hired to take care of something (property or a person); 
2. 
 an official who performs the duties of an office temporarily; 
- Example: "he acted as a caretaker until a new president could be elected"
WordNet (r) 3.0 (2006):
caretaker
    n 1: a custodian who is hired to take care of something
         (property or a person)
    2: an official who performs the duties of an office temporarily;
       "he acted as a caretaker until a new president could be
       elected"
Moby Thesaurus II by Grady Ward, 1.0:
23 Moby Thesaurus words for "caretaker":
   air warden, attendant, castellan, conservator, curator, custodian,
   forest ranger, game warden, gamekeeper, governor, guardian,
   guardian angel, janitor, keeper, lifeguard, lifesaver, next friend,
   prochein ami, ranger, shepherd, steward, warden, warder