IPA: /ˈɡaɪl.fəl.i/
KK: /ˈɡaɪl.fəl.i/
In a way that is clever and deceitful, often to achieve a goal or trick someone.
She guilefully convinced her friends to help her with the project by making them believe it was their idea.
Guilefully → It is formed from "guile" (from Old French *guile*, meaning deceit or trickery) and "-fully" (meaning in a manner full of). The word "guilefully" means in a manner full of deceit or trickery.
Think of 'guile' as deceit and remember that 'guilefully' means acting in a deceitful manner.