(as) innocent as a lamb
1. Blameless or faultless. I swear, I didn't pull the fire alarm—I'm innocent as a lamb!
2. Unsophisticated, inexperienced, and/or gullible. This is her first job—she's as innocent as a lamb.
*innocent as a lamb
and *innocent as a newborn babe 1. guiltless. (*Also: as ~.) "Hey! You can't throw me in jail," cried the robber. "I'm innocent as a lamb."
2. naive; inexperienced. (*Also: as ~.) She's eighteen years old, but innocent as a newborn babe.