Big C
noun
1
cancer US, 1964.
2
cocaine US, 1959.
3
commitment to a relationship seen as something to be feared or avoided UK, 2003.
4
in citizens' band radio slang, applied to many UK towns beginning with C, specifically Caernarfon, Carlisle, Chichester or Chippenham. This logic is continued throughout the alphabet, e.g. 'big B by the sea' (Brighton), 'big D' (Dorchester), 'big W' (Worthing); also, villages beginning with C become 'little C' or, in Scotland, 'wee C' UK, 1981.
5
a female as an sexual object. A hint of CUNT US, 1963.
6
a railway conductor US, 1968