The adjective deceiving can be used in this sense, as in Looks can be deceiving. Example: A lot of advertising is intended to deceive us into thinking we need something.

What is the adjective form of deceit?

deceitful. deliberately misleading or cheating. deceptive in multiple ways, twifaced.

Is deceit a noun or adjective?

The word deceit often implies a pattern of behavior, rather than a one-time act. The adjective deceitful can describe something that deceives or is intended to deceive, or someone who is known for engaging in deceit.