Depth (literal):
* The lake was too shallow for the boat to sail properly.
* We waded into the shallow end of the pool.
Depth (figurative):
* His understanding of the subject was shallow, lacking any real depth.
* Her interest in the project was shallow, she only cared about the reward.
Other meanings:
* The actress played a shallow character who only cared about appearances.
* He was a shallow person, only interested in superficial things.
In a negative way:
* The book offered a shallow analysis of the historical events.
* Their relationship was shallow and lacked any real substance.
In a neutral way:
* The pool was shallow enough for young children to play in safely.
* The river was shallow at this point, making it easy to cross.