expression, noun
ascetic practice of silence
A Buddhist training in which one refrains from speaking for a set period, often undertaken in a temple or during a retreat.
彼は一週間の無言の行を終えて、心が澄んだと言った。
After finishing a week-long practice of silence, he said his mind felt clear.
From 無言 (mugon, 'silence') + の (no, possessive particle) + 行 (gyō, 'ascetic practice'). The term is specific to Buddhist contexts.