plural defects
: a problem or fault that makes someone or something not perfect: such as
a
: a physical problem that causes something to be less valuable, effective, healthy, etc.
This small defect [=flaw] greatly reduces the diamond's value.
They examine their products for defects.
a minor/major defect
She was born with a heart defect.
a birth defect [=a physical problem that someone is born with]
b
: something that causes weakness or failure
We had to point out the defect [=flaw] in their logic.
Vanity and pride were his two worst character defects.
defects; defected; defecting
formal
: to leave a country, political party, organization, etc., and go to a different one that is a competitor or an enemy
The Russian scholar defected in 1979.
She defected from the conservative party.
He defected to the West before the war began.
The reporter defected to another TV network.
Cite this Entry
“Defect.” Merriam-Webster.com Simple Definition, Merriam-Webster, https://www.merriam-webster.com/simple/defect. Accessed 17 Apr. 2026.
Copy Citation
