-vua ("to undress") is the conversive of -vaa ("to wear").
Kofia comes from Arabic كُوفِيَّة (kūfiyya, "keffiyeh"), of which the English Wiktionary does not state the origin. However, "cap" in Spanish is said cofia, to which the Wiktionary asigns a West Germanic origin, akin to English coif and French coiffer. Things shall you see…
Why not 'you are taking off a hat'? Kofia can be either a hat or the hat so both should be accepted
It's hard to imagine a context for this translation. "You are taking off your hat" is normal English but not accepted here.