Tolerance

Tolerance to alcohol means your body is no longer as sensitive to alcohol.  Someone with a high tolerance may be "able to hold their liquor" meaning they will not show the objective signs of intoxication.  However, their BAL may be dangersouly high and they may have poor judgement leading to decisions about driving, sexual activity, or leading to other unwanted consequences.  Tolerance is what happens when someone needs to drink more to feel the effects of alcohol.