Fake is more used as a adjective to describe the quality of something that isn't genuine. Example: fake designer clothes Fake friend. Fake jewelry Pretend is more used as a verb to describe a person's action that isn't reality. Examples: I pretended to be his girlfriend to help him impress his parents. I pretended to be walking through a majestic corridor when I was in reality walking through a back alley. Hope this makes sense

pretend and fake are both synonyms of each others both means to act unknowing when one knows. basically to lie the only difference is probably pretend being an indefinite or long term action where as fake is more a short term or one off action.

"Pretend" is usually about playing a game, like Monopoly money. "Fake" is usually to trick someone and take advantage of them, like counterfeit money, a crime.