into one's shell{adv.} or {adj. phr.}, {informal} In or into bashfulness; into silence; not sociable; unfriendly.
After Mary's mother scolded her, she went into her shell. The teacher tried to get Rose to talk to her, but she stayed in her shell. Contrast: OUT OF ONE'S SHELL.
See: IN ONE'S SHELL.
[TahlilGaran] English Idioms Dictionary ▲