The phrase "poses as" implies someone who is pretending to be something they are not, often with deceitful intentions. There are several synonyms that can be used to convey the same meaning such as "impersonates," "masquerades as," "fakes," or "assumes the identity of." Other options include "mimics," "plays the part of," "camouflages as," or "feigns." These synonyms can be useful in avoiding repetition or adding different shades of meaning to a sentence. However, it's important to choose the right synonym that accurately represents the intended meaning and fits well in the sentence.