If not and Without

If not adverb - Perhaps; indicating possibility of being more remarkable (greater or better or sooner) than.

Without and if not are semantically related. in other than topic. In some cases you can use "Without" instead the phrase "If not" as a conjunction or a preposition, when it comes to topics like except that.

Without preposition - Not having.

If not and without are semantically related. You can use "If not" instead the word "Without" as a conjunction or a preposition.