In the following question, four words have been given out of which one word is incorrectly spelt. Select the incorrectly spelt word.

Introduction / Context:
This spelling question asks you to spot the one incorrectly spelt word out of four. Such questions test not just memory but also your familiarity with common academic and descriptive vocabulary. Being able to recognise correct forms quickly is useful both in exams and in real-life writing.

Given Data / Assumptions:

The four main words to check are: disparage, diabolical, discrepeancy, and disheveled (plus an extra correct form given as a distractor in the options list).

We assume American spelling is acceptable for "disheveled" (one "l"), though "dishevelled" is common in British English, and both are recognisable.

Our task is to identify the option that is clearly not a standard spelling of any accepted English word in this context.

Concept / Approach:
The correct spelling of the word meaning "an inconsistency or difference between two things" is "discrepancy", not "discrepeancy". The vowels in the middle are "e" followed by "p" and then "a": d-i-s-c-r-e-p-a-n-c-y. "Disparage" (to belittle), "diabolical" (devilish, very bad), and "disheveled" (untidy, messy) are all correctly spelt in standard English. Therefore, "Discrepeancy" is the only clear error.

Step-by-Step Solution:
Step 1: Check "Disparage": this is correctly spelt; it means to criticise or belittle someone. Step 2: Check "Diabolical": this is correctly spelt; it means relating to the devil or extremely bad. Step 3: Check "Disheveled": in American English, one "l" is standard; in British English, "dishevelled" has two "l"s, so the version shown is still acceptable. Step 4: Examine "Discrepeancy": this is not the standard spelling; the correct word is "Discrepancy" with "a" after the "p", not "e". Step 5: Confirm with the extra correct form "Discrepancy" that "Discrepeancy" is indeed the wrong variant.

Verification / Alternative check:
Use the correctly spelt forms in example sentences: "There is a discrepancy between the two reports." Here, "discrepancy" fits naturally. If we substitute "discrepeancy", the word looks wrong and would not be accepted in formal writing or by standard dictionaries. Similarly, sentences like "He tends to disparage his colleagues" and "The room was completely disheveled" show regular, widely accepted spellings. This comparative check confirms that "Discrepeancy" is the incorrect form.

Why Other Options Are Wrong (as incorrect choices):
Option A Disparage is a correctly spelt verb meaning to speak of someone in a negative or belittling way.
Option B Diabolical is correctly spelt and used to describe something extremely bad or evil.
Option D Disheveled is a standard American spelling for "untidy or disordered" in appearance; it is not a misspelling.
Option E Discrepancy is the correct form of the word for inconsistency, included here to highlight the error in "Discrepeancy".

Common Pitfalls:
Learners often confuse patterns like "-ancy" and "-ency" as well as the placement of vowels before consonants. For words like "discrepancy", a helpful memory aid is to break it into "discrep + ancy" rather than "discrepe + ancy". Additionally, seeing a correct form like "Discrepancy" in the same list can guide you to recognise the error in "Discrepeancy". Always compare suspicious-looking forms with known patterns and similar words you are confident about.

Final Answer:
The incorrectly spelt word is "Discrepeancy".