匿 is compound ideograph. 匸 resembles a container or a wall, and 若 depicts a woman. 匿 originally meant a woman hides away.
匿 was written as乚 +in the oracle bone script, but this part 乚 was changed to 匸 in the later scripts.
See the character 若.
The original meaning of 匿 remains until now. You can see the meaning of “hide” still stays the same in the 匿 related words such as 隐藏，藏匿，逃匿, etc.