The most common and most likely answer to this crossword clue is the 5 letter word NULLS
N
U
L
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S
Buddy explains!

The straight part
We know that "Invalidates" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case invalidates = nulls.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does NULLS mean?
NULLS noun- A non-existent or empty value or set of values.
- Zero quantity of expressions; nothing.
- Something that has no force or meaning.
- The ASCII or Unicode character (␀), represented by a zero value, that indicates no character and is sometimes used as a string terminator.
- The attribute of an entity that has no valid value.
- One of the beads in nulled work.
- Null hypothesis.
- To nullify; to annul.
- To form nulls, or into nulls, as in a lathe.
- To crack; to remove restrictions or limitations in (software).