Three words become their own opposites when the same letter is placed before them. What are the words, what is the initial letter that changes them, and what are the new - opposite - words?

HINTS:

The meanings of the original words:

1. Go

2. Open

3. Injure 

The meanings of the words after the initial letter is added:

1. Stay

2. Secret

3. Amuse

Answers:

 

1. LEAVE - CLEAVE*

2. OVERT - COVERT

3. HARM - CHARM 

 

CLEAVE is especially interesting because it is a contronym - or self-contradictory word. It can mean to stay close to - as in the example above - or it can mean to separate.