IPA: /nɒnˈkɒŋɡruːənt/
KK: /nɑnˈkɑŋɡruənt/
Not in agreement or harmony; not having the same shape or size.
The two triangles are noncongruent because they have different angles and side lengths.
Noncongruent → It is formed from "non-" (meaning not) and "congruere" (meaning to agree or correspond). The word describes things that do not agree or correspond with each other.
Think of 'not' ('non-') agreeing or corresponding ('congruere') — that's why noncongruent means things that do not match.