knee-high to a grasshopper

knee-high to a grasshopper also knee-high to a duck  {adj. phr.},  {informal}
As tall as a very small child; very young.
Charles started reading when he was knee-high to a grasshopper.
I've known Mary ever since she was knee-high to a duck.
Categories: adjective informal

'knee-high to a grasshopper' on video