IPA: /əˈrɛsti/
KK: /əˈrɛsti/
A person who has been taken into custody by law enforcement because they are suspected of committing a crime.
The arrestee was taken to the police station for questioning.
Arrestee is formed from "arrest" (from Old French *arrestier*, meaning to stop or seize) and the suffix "-ee" (meaning a person who is the recipient of an action). The word "arrestee" refers to a person who has been stopped or seized by law enforcement.
Think of someone who has been 'stopped' ('arrest') and is now the 'recipient' ('-ee') of that action — that's why an arrestee is a person who has been arrested.