noun
Refers to a person who copies another's style, behavior, or work. Can be neutral or slightly negative depending on context.
彼は有名な歌手の模倣者として知られている。
He is known as an imitator of a famous singer.
その画家の作品には模倣者が多い。
That painter's works have many imitators.
偽物 is a fake or counterfeit object, not a person. 模倣者 is specifically a person who imitates.
Compound of 模倣 (imitation) and 者 (person). The exact historical derivation is uncertain, but the kanji are conventionally associated with the meaning.