inattentive
in-at-ten-tive
adjective
Failing to pay proper attention; not noticing things around you.
"The driver was inattentive and missed the turning."
Thesaurus
Synonyms: drowsy, distrait, absentminded, distracted, woolgathering, scatty, yawning, absent, abstracted, oblivious, forgetful, moony
Antonyms: attentive