What is trademark infringement?

The use without consent of the trademark owner of any a) reproduction, b) counterfeit, c) copy or d) colorable imitation of any registered mark or tradename in connection with the sale, offering for sale, or advertising of any goods, business or services on or in connection with which such use is likely to cause confusion or mistake or to deceive purchasers or others as to the source or origin of such goods or services, or identity of such business; or reproduce, counterfeit, copy or colorably imitate any such mark or tradename and apply such reproduction, counterfeit, copy or colorable limitation to labels, signs, prints, packages, wrappers, receptacles or advertisements intended to be used upon or in connection with such goods, business or services (Esso Standard Eastern v. CA, G.R. No. L-29971, Aug. 31, 1982)