使劲
shǐ jìn · HSK 4
to exert all one's strength
💪 使 = use/apply + 劲 = strength/force
使 means to use or employ, 劲 means strength or vigor. Together: to apply force — to exert all one's strength. Often used like 'give it your all' when pushing, pulling, or working hard.
使 — person radical 亻 + official 吏
Originally a phono-semantic compound: 亻 (person) gives the meaning and 吏 (official, also a phonetic clue) suggests the sound. The early sense was 'to send a person on a mission,' from which came 'envoy/messenger' and the broader meanings 'to use' and 'to cause/make.'