afraid of own shadow
afraid of (one's) own shadow
Easily scared; jumpy; timid. Everyone was surprised that Janice led the meeting with confidence, as she normally seems afraid of her own shadow. Please don't take my sister to a haunted house on Halloween—she's afraid of her own shadow.
afraid of one's own shadow
Fig. easily frightened; always frightened, timid, or suspicious. (An exaggeration.) After Tom was robbed, he was even afraid of his own shadow.