The phrase "hands in" can be used in various contexts such as submitting a document, raising one's hand to answer a question or to surrender oneself. There are several synonyms that can be used in place of this phrase depending on the situation. For example, instead of saying "hands in your assignment", one could say "submit your assignment", "turn in your task" or "hand over your work". Similarly, synonyms for "hands up" could be "raise your hand", "stop", "surrender yourself" or "yield". It is important to choose the right synonym to effectively communicate the intended meaning in any given circumstance.