No, vocabulary is the most important part of learning a language if you want to use to it to actually communicate, or consume media in that language. And learning vocabulary takes a lot of time. You can join exactly zero conversations about everyday topics without knowing at least a few hundred, better a few thousand words. You can't even read stories for toddlers without knowing a few hundred words. Grammar won't help you understand sentences if all the meaning you extract is Noun (singular, female) Verb (present tense) Object (plural, neutral).
Learning grammar on the other hand is relatively easy, because there are far fewer rules to remember and you naturally develop a "feeling" for correct sentence structure after you've used the language enough, even passively.
Learning grammar on the other hand is relatively easy, because there are far fewer rules to remember and you naturally develop a "feeling" for correct sentence structure after you've used the language enough, even passively.