Convert these adjectives into nouns. You may use a dictionary.

Gap-fill exercise

Fill in all the gaps, then press "Check" to check your answers. Use the "Hint" button to get a free letter if an answer is giving you trouble. You can also click on the "[?]" button to get a clue. Note that you will lose points if you ask for hints or clues!
Adjective  Noun 
simple
flexible
sad   
dark   
stupid
popular
happy
punctual