Dictionary.com
definitions

erk

[urk]
noun British Slang.
  1. an aircraftsman of the lowest rank in the Royal Air Force.
  2. a worthless, stupid person; jerk.

Origin of erk

First recorded in 1920–25; earlier naval slang for any noncommissioned rank; of uncertain origin
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for erk

erk

noun
  1. British slang an aircraftman or naval rating

Word Origin for erk

C20: perhaps a corruption of AC (aircraftman)
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012