the bleating of the deer
呦 represents the bleating sound of a deer, a specific vocalization. It is a rare character with no broader abstract meaning.
呦 combines 口 (mouth) with 幼, which likely contributes the sound, to represent a deer's bleat. The exact historical development is uncertain.
The mouth 口 on the left and the young 幼 on the right suggest a young deer making a soft bleating sound through its mouth.
For ユ, imagine a young deer bleating 'you' softly: you -> ユ, and the sound comes from its mouth 口.
crying (of a deer)