1.
different person, someone else entirely
A completely different person. Often used figuratively to describe someone who has changed so dramatically in appearance, personality, or behavior that they seem like a different person.
まるで別人のようだ。
It's as if they're a completely different person.
ダイエットに成功して別人みたいになった。
After successfully dieting, they look like a completely different person.
久しぶりに会った彼は別人のように明るくなっていた。
When I met him again after a long time, he had become so cheerful he seemed like a different person.
別人 literally means "different person" and is most often used figuratively to describe dramatic transformation.
COMMON PATTERNS:
- 別人のようだ: to be like a different person
- まるで別人: just like a different person
- 別人みたいになる: to become like a different person
- 別人に生まれ変わる: to be reborn as a different person
TYPICAL CONTEXTS:
- Dramatic weight loss or gain
- Change in personality or attitude
- Appearance change (haircut, makeup, aging)
- Skill improvement (sports, music)
The figurative use is far more common than the literal meaning. Saying 別人みたい is a strong compliment or observation about how much someone has changed.