I see the claim that acutilobate is a “dictionary-only” word, for example seen in the 1913 Webster’s dictionary. How would a word get into a dictionary that only appears in dictionaries and is not really a word in use? Once a word is in a dictionary such as Webster’s doesn’t that confer it life and wouldn’t it generally begin to enter the language in actual use? Websters defines it as a botany term: “Having acute lobes, as some leaves”. Where did acutilobate originate from as a word?
The word very likely comes from the Latin acutilobus:
Searching for "acutilobus" in Wikipedia yields:
As an adjective, acutilobate could well have been/still be used to describe such plants. Or perhaps it has since been superseded by some other term which has attracted the fancy of botanists worldwide. In any case, that does not mean that the word should no longer be in the dictionary. Some words survive. Some don't. This one very likely didn't, unlike its second cousin twice removed, acutilingual—meaning "having a sharply pointed tongue or mouth, as certain bees"—which has found a curious niche to survive in.