Please explain the differences between those similar words [closed]
Solution 1:
This is a bad exercise because character and nature would also be valid in the literal sense.
To show one's true colours is a metaphor, referring to the tradition of a warship flying the flag of a different nation as a ruse to enable it to get close to an enemy ship. This was acceptable as long as it changed to the correct flag (its 'true colours') before attacking.