刺激
cìjī · HSK 4
stimulate
⚡ 刺 = thorn/prick + 激 = surge; a thorn that surges the nerves
刺 means to pierce or prick (think of a thorn jabbing); 激 means to surge or rouse (water striking rock). Together: a jab that rouses — stimulate, provoke, irritate. The English 'jolt' captures both senses well.
刺 — thorn 朿 (phonetic) + knife 刂 (meaning)
A semantic-phonetic compound. The knife radical 刂 carries the meaning of cutting or piercing, while 朿 (a thorn) supplies both the sound and reinforces the idea of something sharp. Original sense was 'to stab' or 'pierce', later extended to 'thorn', 'sting', and figuratively 'to criticize sharply'.