Legitimate interest is one of the GDPR's legal bases for processing personal data, covering uses that are necessary for a business purpose and do not.
Prior consent means non-essential cookies and trackers must stay off until the visitor actively agrees. Consent given after scripts have already.
The ePrivacy Directive is the EU law that requires consent before storing or accessing information on a visitor's device, which is what makes cookie.
Dark patterns are banner designs that push visitors toward accepting: a bright accept button with a hidden reject option, confusing wording, or extra.