Can you explain what it means to be above the legal limit for drinking?

You're drunk!: If you do not drink regularly and therefore have developed a 'tolerance' to a higher blood alcohl level (which is clearly not a reason to commence a path to alcoholism, then being abov eth 'legal limit' generally means you're drunk. Your judgement is impaired...Etc etc.

Blood alcohol level: If 18 or over, elevated is considered .08 or greater (that is .08gm/dl or 80 mg/dl). If under 18, an elevated level can be considered as low as .02. Value must be evaluated in terms of dilution, (amount of alcohol per a specified volume of blood). This of course varies depending upon the proof of the beverage (proof is approximately 2x the ethanol (alcohol) percentage).