He kept his mouth sealed and refused to answer any questions.
Tips
usage
缄 most commonly appears in the compound 缄默 (jiānmò, to keep silent) and the set phrase 缄口不言 (jiān kǒu bù yán, to keep one's mouth shut). It is a literary word rarely used in isolation.
Left-side silk radical, the simplified side-form of 糸. 缄 originally meant the cord used to bind and seal a wooden tablet or a letter-bundle, so the thread radical is literal. Same binding family: 结 (knot), 绑 (tie), 缚 (bind), 绳 (rope).
Right side 咸 supplies the sound - xián drifting to jiān through the regular j/x alternation in old readings. Same phonetic family: 喊 (shout), 减 (reduce), 感 (feel). 缄 is mostly used in 缄默 (to keep silent) and 缄口 - both about staying sealed and unspoken.
