Hi,
If you go to the documentation here on Mashape, you’ll see a section to the right of the page that shows examples in multiple languages. Under the Curl definition, you should see something like this:

curl --get --include ‘https://wordsapiv1.p.mashape.com/words/bump/also’
-H ‘X-Mashape-Key: yourKeyIsHere’
-H ‘Accept: application/json’

https://market.mashape.com/wordsapi/wordsapi

You can use the key listed there in your header request.