Definition of on that ground:
°Below the ground; below the surface of the Earth.
"There is an underground tunnel that takes you across the river."
°Hidden, furtive, secretive.
"These criminals operate through an underground network."
°Below the ground.
"The tunnel goes underground at this point."
°Secretly.
°(with the) A movement or organisation of people who resist political convention.
Definition of on that ground:
°Below the ground; below the surface of the Earth.
"There is an underground tunnel that takes you across the river."
°Hidden, furtive, secretive.
"These criminals operate through an underground network."
°Below the ground.
"The tunnel goes underground at this point."
°Secretly.
°(with the) A movement or organisation of people who resist political convention.