1
general::
Yield to a stronger force, retreat, as in He began to give ground on that point, although he didn't stop arguing entirely. This expression originated in the 1500s, when it alluded to a military force retreating and so giving up territory to the enemy. By the mid-1600s it was being used figuratively.
American Heritage Idioms
2
general::
Phrase(s): give ground
1. Lit. to retreat, yielding land or territory. • I approached the barking dog, but it wouldn’t give ground. 2. Fig. to "retreat" from an idea or assertion that one has made. • When I argue with Mary, she never gives ground.
McGrawhill's American Idioms And Phrasal Verbs