Meritorious describes honorable or admirable people, actions, and creations:
The soldier who risked his life for his comrades received a medal for meritorious action.
Bach’s works are considered among the most meritorious compositions of the Baroque period.
Meretricious, in contrast, describes people, actions, and creations that falsely present themselves as valuable—but which are deceptive, superficial, insincere, or simply cheap:
The politicians’ meretricious claims about caring for the poor were not believed.
Some people consider commercial pop music a meretricious wasteland.
Meretricious also means “like a prostitute;” however, since this meaning is wrongly insulting to prostitutes, it should be used carefully, it not avoided. Meretricious is also not a commonly used word.