Here are some examples:

    take off vs. takeoff

take off (verb)

To leave the ground and begin to fly:

•  "The plane will take off in 10 minutes."

To become successful or popular:

•  "Her career really took off after that big project."

takeoff (noun)

The act of leaving the ground:

•  "The takeoff was smooth despite the stormy weather."

    break down vs. breakdown

break down (verb)

To stop functioning (for machinery):

•  "My car always seems to break down at the worst times."

breakdown (noun)

A failure to function properly:

•  "The breakdown of the system caused major delays."

To lose emotional control:

•  "I had a mental breakdown after working 80-hour weeks."

    work out vs. workout

work out (verb)

To exercise:

•  "I try to work out at least three times a week."

To resolve or find a solution to a problem:

•  "We need to work out a plan before the meeting."

workout (noun)

A session of physical exercise:

•  "That was an intense workout! I'm exhausted."

    set up vs. setup

set up (verb)

To arrange or organize something: 

• "Can you help me set up my new computer?"

To trick someone: 

• "Someone cleverly set them up. They were tricked into attending the event."

setup (noun)

The arrangement or organization of something: 

• "The setup for the concert took hours."

    break through vs. breakthrough

break through (verb)

To make an important discovery or achievement:

•  "Scientists hope to break through in cancer research soon."

To force a way through a barrier:

•  "The firefighters managed to break through the flames to rescue the trapped residents."

breakthrough (noun)

An important discovery or achievement:

•  "This discovery could be a major breakthrough in medicine."