WHATīS THE MEANING OF " ONESELFīS ADAM APPLE" ?
One's (not oneself's) Adam's apple.
The Adam's apple is the lump men have at the front of their neck, on the throat.
Laryngeal prominence - Wikipedia, the free encyclopedia
"One's" means "belonging to one (a person)".
"One's Adam's apple can be quite big" = "A person's Adam's apple can be quite big".