Select the INCORRECTLY spelt word.

The correct option to be selected is Judgment.

Let's analyze the given words:

1. Relevant: Correctly spelt. It means closely connected or appropriate to what is being done or considered.

2. Chief: Correctly spelt. It means a leader or ruler of a people or organization.

3. Judgment: In British English, the preferred spelling is often Judgement (with an 'e'), though "Judgment" is standard in American English and legal contexts. Given the specific answer key provided, Judgment is identified as the target word.

4. Colleague: Correctly spelt. It means a person with whom one works in a profession or business.

Therefore, the word indicated as incorrect according to the answer key is Judgment.