defect-n; 3 Senses

Sense Number 1: a state of malfunction

Commentary: DEFECT[+state][+malfunction]
NOTE: refers to systemic malfunction, deformity, not a simple mark, blemish (Sense 3)

The drug has been linked to certain types of birth defects.
He has a slight speech defect.
They discovered a defect in the pressure gauge. (It was not operating properly)

WordNet 3.0 Sense Numbers: 1

Sense Number 2: a lack, deficiency, shortcoming

Commentary: DEFECT[+state][+deficiency]

There are grave defects in that nation's foreign policy.
One defect of this cookbook is that the recipes tend to be high in fat.
The physicist calculated the mass defect of the carbon atom. (amount by which mass of nucleus is less than sum of masses of constituent particles)

WordNet 3.0 Sense Numbers: 2

Sense Number 3: a blemish or mar on an object, form

Commentary: DEFECT[+entity][+form][+blemish]

She inspected the garment for defects.
There is a slight defect in the glass of this window pane.
The teenager considered her strong chin a defect. (a flawed feature)

WordNet 3.0 Sense Numbers: 3, 4