We should guard against our \(\textbf{green-eyed friends.} \)
To answer this question, we need to understand the meaning and context behind the phrase \(\textbf{green-eyed friends.}\).
The term "green-eyed" is often used metaphorically to refer to jealousy. This expression originates from the idea of "green-eyed monster" used by Shakespeare in his play "Othello," where it describes jealousy as a monster that consumes individuals. Therefore, a "green-eyed friend" would metaphorically mean a jealous friend.
Let's evaluate the given options:
Based on the above explanation and analysis, the correct answer is "jealous."