Definition of "GRU"

GRU

proper noun
1. The Main Intelligence Directorate — the Soviet and then the Russian military intelligence agency.
  Quotations
  Apparently nobody ever expects the GRU, Russian Military Intelligence.
  2020, Ben Aaronovitch, False Value, Gollancz, page 115
  A team of investigators claim to have unmasked a deep-cover spy from Russia’s military intelligence agency, the GRU, who spent a decade posing as a Latin American jewellery designer and partied with Nato staff based in Naples.
  2022 August 26, Shaun Walker, “Socialite who charmed Nato staff in Naples was Russian spy, say investigators”, in The Guardian‎