"Knee deep" is an expression that is often attached to the depth of water, but it can also be used to describe any situation that is challenging or demanding. Synonyms for this phrase that may be used instead include "in the thick of things", "immersed", "up to your neck", "embroiled", "swamped", or "overwhelmed". These words can provide a vivid and engaging way to describe the level of difficulty or involvement required in a particular task or situation. Using synonyms for "knee deep" can help to add depth and variety to your language use, making your communication more accurate and interesting.