"Having a tongue like a cow, smooth one way and rough the other; and hence, one who gives fair or foul
language as may suit his purpose."
~Thomas Wright's 'Dictionary of
Obsolete and Provincial English,' 1857
One who speaks with
eloquence one moment, then swears like a sailor the next, depending on the mood or situation.
Gen George S. Patton was very cow tongued.
One minute he could be giving an
eloquent speech & the next minute, cuss someone out with
language that would make a whore blush.