believes is a verb in English and is not related to Greek language
3rd person singular of the verb "croire" ("to believe"): He believes.
herpeton is the reptile in greek comes from the verb herpo -> to creep
Ancient Greek
It is Latin, from the verb 'serpo,' meaning to creep or crawl.
It means ''to play'' (παίζεις). Original verb paizo (παίζω).
The Greek verb phagein means "to eat", as in phagocyte or "eating cell"
Of the Greek verb βλώσκω blōskō "to come", meaning "having come". Ancient Greek does not; the object them is understood from context.
The verb forms for the noun belief are believe, believes, believing, believed.
the ancient Greeks
The plural of the noun belief is beliefs.Example: There are many beliefs within this society.The word believes is the third person, singular, present of the verb to believe.Example: He believes that he can win.
erxomai is an ancient Greek verb meaning to come and to go. This is the first person, singular, middle-passive form.
if by "laugh" you mean the verb that would be Γελάω (yelao)