(British, informal) Abbreviated form of locum tenens.The Concise Oxford English DictionaryEdition
1915, W. Somerset Maugham, "", :-- "I suppose you wouldn't like to do a locum for a month on the South coast? Three guineas a week with board and lodging." -- "I wouldn't mind," said Philip. -- "It's at Farnley, in Dorsetshire. Doctor South. You'd have to go down at once; his assistant has developed mumps. I believe it's a very pleasant place."