jū​jǐn

reserved

拘谨 (拘謹) jū​jǐn
reserved adjective
stiff, restrained, or ill at ease in social interactions

He appears a bit reserved in front of strangers.

overcautious adjective
excessively careful or rigid in one's actions or creative style

His writing style is too stiff and lacks flexibility.

Frequency

Movie subtitles
1.16 per million appears in 1% of films
Written text
1.42 per million

Sources

Definitions
CC-CEDICT