grasshopper

To be young. When I was knee-high to a grasshopper, I loved playing with dolls and stuffed animals. Unfortunately, Ed's mother died when he was still knee-high to a grasshopper.

Rur. very small or short. (Usually used to describe children. *Typically: be ~; since someone was ~.) I've known you since you were knee-high to a jackrabbit. My, how you've grown! The last time I saw you, you were knee-high to a grasshopper!

to be very young The last time I came here I was knee-high to a grasshopper.

Quite young, as in I haven't seen him since I was knee-high to a grasshopper. This hyperbolic expression, dating from about 1850 and alluding to someone's youth, replaced the earlier knee-high to a mosquito or bumblebee or splinter.

Very young. A grasshopper is tiny, and to stand, metaphorically speaking, no higher than the insect's knee was to be very small or young or both. The expression was usually used by male relatives to point out either a child's youth (“Drive the tractor by yourself?— why, you're not even knee-high to a grasshopper”) or the speaker's experience (“I've driven tractors since I was knee high to a grasshopper”).