"In the thick of" is a phrase that signifies being deeply immersed or involved in something. There are many synonyms that can be used to express this meaning. "Engrossed in", "drenched in", "immersed in", "absorbed in", "submerged in", "buried in" are some of the synonyms that can be used interchangeably. These synonyms provide a broader range of expressions that can be used to describe being completely and wholly invested in something. They are useful in providing variety and depth to writing, particularly in creative writing. Using different synonyms can also elevate the quality of communication and make it more engaging and interesting.