noun
not carrying; not having on one's person; nonpossession
Typically used in legal, police, or administrative contexts to refer to the failure to carry a required document such as a driver's license, passport, or residence card. Often appears in compound phrases like 免許不携帯.
免許不携帯で罰金を取られた。
I was fined for not carrying my driver's license.
パスポート不携帯のまま海外に行くのは危険だ。
It's dangerous to go abroad without carrying your passport.
所持 means 'possession' in a broader sense; 不携帯 emphasizes the failure to carry something that should be on one's person, often with legal implications.
Compound of 不 (negative prefix) and 携帯 (carrying, portable). The word is a straightforward Sino-Japanese formation.