noun which may take the genitive case particle 'no'
at work; working; in the middle of work
Describes the state of being engaged in work, often used with に or as a no-adjective. Common in phrases like 仕事中に (while working) or 仕事中です (I'm working).
仕事中に電話がかかってきた。
I got a phone call while I was working.
今、仕事中なので、後でかけ直します。
I'm working right now, so I'll call you back later.
My father is at work right now, so he can't answer the phone.
I got an urgent phone call while I was working.
I try not to look at my phone while I'm working.
休み means a break or day off, the opposite state of 仕事中, which describes being actively engaged in work.
Compound of 仕事 (work) + 中 (in the middle of). The suffix 中 (ちゅう) indicates being engaged in an activity.