A british weapon during world war i had a cover name of water-closet for russia which became water-this then just this

Below you can find the A british weapon during world war i had a cover name of water-closet for russia which became water-this then just this Jeopardy Words Answer. The answer to A british weapon during world war i had a cover name of water-closet for russia which became water-this then just this has 4 letters. This clue belongs to the Weapons of the 2nd millennium category and is part of Jeopardy Word Level 394. If you scroll near the bottom you will find other clues and answers part of level 394