fake it
Synonym discussion
Sense: phrasal verb/1
All three words describe some form of deception, but each has a different feel. 'Bluff' is most at home in games or competitive situations — you bluff to make opponents believe you hold better cards than you do. 'Pretend' is the broadest term; a child pretending to be a superhero and an adult pretending to enjoy a boring party both work. 'Fake it' sits between them: it always involves a practical pressure to perform (a speech, a job interview, playing an instrument), and it carries the idea that you are covering up a real lack of ability to get through a specific moment. 'Put on an act' is more theatrical and suggests a sustained performance rather than a quick cover-up. In everyday conversation, a colleague who has no idea how to use the software but opens it anyway and clicks confidently is faking it; a poker player who raises her bet with a weak hand is bluffing; a child who tells her mother she is a dragon is pretending.
Etymology
The verb 'fake' first appeared in 18th-century British thieves' cant, possibly from German 'fegen' (to sweep) or an older word 'feague' (to make something look better than it is). By the 1800s it meant to counterfeit or forge. The phrase 'fake it' emerged in early 20th-century American show business, where performers who forgot their lines would 'fake it' — improvise convincingly on stage. The motivational saying 'fake it till you make it' spread through self-help books in the 1970s.