charlatan = a person falsely claiming to have a special knowledge or skill.

 charlatan

/ˈʃɑːlət(ə)n/

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noun

noun: charlatan; plural noun: charlatans

1. a person falsely claiming to have a special knowledge or skill.

   "a self-confessed con artist and charlatan"

cantankerous = bad-tempered, argumentative

 can·tan·ker·ous

[kanˈtaŋk(ə)rəs]

ADJECTIVE

1. bad-tempered, argumentative, and uncooperative:

   "he can be a cantankerous old fossil at times"