The phrase "go woolgathering" generally refers to a person who is lost in thought or daydreaming. However, there are several other phrases in the English language that can be used interchangeably with this expression. Some common synonyms for "go woolgathering" include being lost in thought, daydreaming, deep in thought, in a reverie, or being lost in contemplation. Each of these phrases describes a person who is absorbed in their own thoughts or mind, often to the point of being unaware of their surroundings. Whether you use "go woolgathering" or another phrase, the meaning remains the same - someone who is completely lost in thought.