locum tenens
Concise Oxford English Dictionary © 2008 Oxford University Press:
locum tenens /ˌləʊkəm ˈtiːnɛnz, ˈtɛn-/
▶noun (pl. locum tenentes /tɪˈnɛntiːz, tɛ-/) a temporary deputy, especially one acting for a cleric or doctor.
'locum tenens' also found in these Oxford entries:

