mistake (someone/something) for (someone/something)

to think that a person or thing is really someone or something else.

The prison buildings could almost be mistaken for a college campus.

• be as stiff as a ramrod
• be as straight as a die
• be as straight as a ramrod
• be as strong as an ox
• be as stubborn as a mule
• be a star in the making
• be as thick as thieves
• be as thick as two short planks
• be as thin as all get out
• be as thin as a rake
• be as thin as a stick
• beast of burden
• be as tough as old boots
• be as ugly as sin
• be a sure thing
• be as white as a sheet
• be as white as snow
• beat about the bush
• beat a dead horse
• beat a hasty retreat
• be a tall order
• be at a loose end
• be at a loss
• beat a path to door
• beat a path to someone's door