In order to diversify your vocabulary, here is a strategy that can help you.
1. Visit the Oxford Dictionary Online.
First, visit the Oxford Dictionary Online. (You can access it by typing oald8.com into your browser’s address bar.)
Find the following words there: commence, terminate and endeavour. You will see that they are all marked as “formal”.
Read the definitions and think of an informal alternative. Then, check further down to see whether you were right.