In "He is a weak man who acts as if he knew everything", does it mean that every man who acts as if he knew everything is a weak man(he = every man. Like in "He is a clever man who plays the fool") or does it mean that you are talking about a specific man, maybe a friend, and "he" is a week man but who acts as if he knew everything." ?
(FYI - s/b knows, not knew)
Imo, both are possible, but this is almost certainly a specific person because they use "he" instead of "it".
Specific: He is a weak man who acts as if he knows everything.
General: It is a weak man who acts as if he knows everything.
as if he knew everything (past tense)
---->This implies he does not know everything as a matter of fact + He is a weak man.
This phrase sounds like it describes a specific man. What is the context of the sentence?