free time; spare time; idle moment
A common phrase meaning 'when one is free' or 'in one's spare time'. Functions as a noun or adverbial phrase.
I watch movies in my free time.
I'm always reading a book when I have spare time.
Variant using the kanji 時 for 'time'.
Phrase composed of 暇 (free time) + な (attributive form of the auxiliary verb だ) + とき (time).