noun
hot flash; rush of blood to the head
Refers to a sudden sensation of heat, often in the face or upper body, from fever, menopause, or emotional excitement.
更年期で、ときどきのぼせを感じる。
I sometimes get hot flashes due to menopause.
熱い風呂に入るとのぼせがくる。
I get a rush of blood to the head when I take a hot bath.
のぼせる is the verb form meaning 'to feel dizzy or flushed from heat or excitement'; のぼせ is the noun describing the sensation itself.
Derived from the verb のぼせる (to feel dizzy or flushed), which itself comes from 上せる (to raise). The noun form のぼせ refers to the resulting sensation of heat or blood rushing to the head.