What's a good word for a lack of concentration?

Solution 1:

The definitions are taken from the NOAD and OALD.

• Distracted adj. unable to concentrate because one's mind is preoccupied.
• Absent-minded adj. tending to forget things, perhaps because you are not thinking about what is around you, but about something else.
• Inattentive adj. not paying attention to something/somebody.

Solution 2:

I think a more simple word would go in this context and the right word to use (if you were to translate מעופף ) would be "daydreamer". You can say "He's such a daydreamer"

Solution 3:

How about absent-minded?

Solution 4:

I can think of:

• daydreaming
• with his/her head in the clouds
• not focused [on the task]
• lost in his/her thoughts