The most common and most likely answer to this crossword clue is the 5 letter word MINUS
M
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N
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S
More clues leading to the result MINUS
- Negative male in America
- Less threatening, to be deprived of all love
- Millions in America finding something negative
- Symbol that’s represented in sum
- Take away copper and half of lead from rear of toy?
- Problem about entertaining at home less
- Operator married across the ocean?
- Leader of Mexicans in America less
- . Briefly contemplate eating at home with take away
- Brahmin uses bottles less
Buddy explains!

The straight part
We know that "Lacking" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case lacking = minus.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 MINUS mean?
MINUS noun- The minus sign (−).
- A negative quantity.
- A downside or disadvantage.
- To subtract.
- Being a negative quantity; pertaining to a deficit or reduction.
- That is below zero by (a specified amount) on a scale.
- Worse off than before; out of pocket.
- Ranking just below (a designated rating).
- Made less or reduced by (followed by an expression of number or quantity).
- Without; deprived of.