maybe not private, maybe not present or manifested as someone; having no conscious individuality; not endued with character.
maybe not relating to someone, or even to any person or persons; having no private research; maybe not bearing the stamp of any specific personality: since, an impersonal comment.
In sentence structure, said of a verb perhaps not used in combination with an individual topic, or employed to state action without requirements of an actor, and therefore used only inside 3rd individual, and often without a subject expressed, or with only the indefinite it (French il, German es, etc.): therefore, Latin me personally tædet, French il m'ennuie, German es urgert mich, it irks myself; or German mich dunkt, methinks —that is. (to) me personally (it) seems (methinks is almost the only real relic left in English for the pure impersonal building without topic); or it rains that is. rainfall is being conducted; or Latin pugnatur, it is fought —that is, battling is being conducted. In lots of quasi-impersonal phrases the it really is a grammatical topic, anticipating a logical topic that comes later on: thus, it hurts anyone to fall —that is, falling hurts one; and so forth.