Refers to closing an open futures position. For an open long, this would be selling the contract. For a short position, it would be buying the contract back (short covering, or covering his short).
LIQUIDATE
Meaning of LIQUIDATE in English
A guide to futures and options market technology English dictionary. Английский словарь-руководство по фьючерсам и опционам рыночных технологий . 2012