The difference between Impersonal and Monopersonal

When used as adjectives, impersonal means not personal, whereas monopersonal means having only one grammatical person.

check bellow for the other definitions of Impersonal and Monopersonal

Impersonal as an adjective:

Not personal; not representing a person; not having personality.

Examples:

"An almighty but impersonal power, called Fate.'' –Sir J. Stephen."
Impersonal as an adjective:

Lacking warmth or emotion; cold.

Examples:

"She sounded impersonal as she gave her report of the Nazi death camps."
Impersonal as an adjective (grammar, of a verb or other word):

Not having a subject, or having a third person pronoun without an antecedent.

Examples:

"The verb “rain” is impersonal in sentences like “It’s raining.”"

Monopersonal as an adjective (grammar):

Having only one grammatical person.