冷やかす
ひやかす · hiyakasu · JLPT N1 · verb-godan
to make fun of
冷 (cold) + やかす (to heat up): teasing someone is making them hot under the collar, a 'cool' jibe that gets a rise out of them
冷 — ice radical 冫 + order 令
A semantic-phonetic compound. The left side 冫 (ice) supplies the meaning of coldness, while 令 (lìng, 'command/order') hints at the pronunciation. Originally referring to the chill of ice, 冷 broadened to mean cold in general, and figuratively cool, indifferent, or detached.