knee-high to a jackrabbit

knee-high to a jackrabbit

1. Very young. A variant of "knee-high to a grasshopper." Wow, I haven't played with one of these old toys since I was knee-high to a jackrabbit. Unfortunately, Ed's mother died when he was still knee-high to a jackrabbit.
2. Diminutive, as in size, stature, or importance. He was knee-high to a jackrabbit all throughout middle school, but in high school he suddenly shot up to 6'2''. I felt knee-high to a jackrabbit when I first joined the massive law firm.
Farlex Dictionary of Idioms.

*knee-high to a jackrabbit

 and *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!
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • knee-high to a duck
  • be as high as a kite
  • near and dear to (one)
  • set (one's) sights high
  • set your sights high/low
  • the heat is on
  • ride high
  • riding high
  • have a high opinion of (someone or something)
  • in high gear