a figment of someone's imagination
US /ə ˈfɪɡmənt əv ˈsʌmwʌnz ɪˌmædʒɪˈneɪʃən/
UK /ə ˈfɪɡmənt əv ˈsʌmwʌnz ɪˌmædʒɪˈneɪʃən/

1.
rekaan imaginasi seseorang, khayalan semata
something that someone has imagined and that does not really exist
:
•
The monster under the bed was just a figment of his imagination.
Raksasa di bawah katil hanyalah rekaan imaginasinya.
•
Her fear of flying is not a figment of her imagination; it's a real phobia.
Ketakutannya terhadap penerbangan bukanlah rekaan imaginasinya; ia adalah fobia sebenar.