Undeclared (adjective)

1. Not having been officially announced or made known.
2. Not having been stated or acknowledged openly.

Origin:

From un- + declared, ultimately from latin declarare, "to make clear or known".

Examples:

1. The war was undeclared, causing confusion among the people.
2. The treasure was undeclared, leading to an investigation.
3. The income was undeclared, resulting in a tax evasion charge.
4. The relationship was undeclared, causing speculation among the public.
5. The candidate was undeclared, leading to speculation about their political intentions.