daydreaming

US /ˈdeɪ.driː.mɪŋ/
UK /ˈdeɪ.driː.mɪŋ/
1.

mơ mộng

the activity of thinking about pleasant things that you would like to do or have happen to you, instead of thinking about what is happening now:

:
We can all admit to occasional daydreaming at work.