The Vietnamese word "khúm núm" is a verb that means to cower or to cringe. It describes a physical reaction of someone who feels afraid, shy, or intimidated, causing them to shrink back or hunch down. This word often implies a sense of submission or reluctance in the presence of someone else.
In summary, "khúm núm" is a verb that vividly describes the action of cowering or cringing in response to fear or intimidation.