To push up or brush back hair (or a small wisp) with one's fingers; to smooth or comb something back.
朝、鏡の前で前髪をかき上げてから出かけた。
In the morning I pushed my bangs back in front of the mirror before going out.
彼は風で乱れた髪を片手でさっとかき上げた。
He quickly brushed his wind-tousled hair back with one hand.
女優は撮影中に顔にかかった髪を何度もかき上げた。
The actress repeatedly pushed the hair off her face during the shoot.