Given that:
$ \begin{gather} \ \text{ art}\hspace{1em}\Leftrightarrow\hspace{1em}\text{phi} \end{gather} $
Can you figure out the words that are missing?
$ \begin{gather} \text{imps}\hspace{1em}\Leftrightarrow\hspace{1em}\text{???}\\ \\ \text{???}\hspace{1em}\Leftrightarrow\hspace{1em}\text{pots}\\ \\ \text{aphid}\hspace{1em}\Leftrightarrow\hspace{1em}\text{???}\\ \\ \text{???}\hspace{1em}\Leftrightarrow\hspace{1em}\text{matzo}\\ \end{gather} $
Every answer is a common English word.