1. not acceptable; not holding acceptable views

ideologically unsound

The use of disposable products is considered ecologically unsound.

2. containing mistakes; that you cannot reply on = unreliable

The methods used were unsound.

3. (of a building, etc.) in poor condition; weak and likely to fall down

The roof is structurally unsound.

Opp: sound

Idiom: of unsound mind: đầu óc rối loạn, điên

unsoundness

Fr: véreux

Decision trees are prone to overfitting, especially when a tree is particularly deep. This is due to the amount of specificity we look at leading to a smaller sample of events that meet the previous assumptions. This small sample could lead to unsound conclusions.