the young man is trying to keep a secret. he doesn't want to speak.

secret keep try hold not want speak silent hidden conceal hush mystery whisper sealed lock guarded veiled covert undercover confidential private classified undisclosed restrained quiet mute mum untold nonverbal unspoken unsaid undivulged unspeakable enigmatic elusive enshrouded masked obscured muffled stealthy concealed disguised hushed wordless