Let’s look at two words. One is microbial and the other is official. These words are changed into adjectives from nouns by adding “ial” at the end of the nouns. A noun describes a thing. An adjective limits or quantifies a noun. For example the soap is microbial. This means that it is a cleaning solution (soap) that has a property of killing microbes. We wouldn’t say “the soap is microbe” because that would be saying that the soap is a microbe which is what I just said twice.
Now let’s look at the word official. The noun would be office. Remember a noun describes a thing. The office is a place where people do business in a closed setting usually, possibly handling paperwork, discussing ideas, interviewing candidates for a job, firing someone, the office is many things. So when someone says that something is official it is office like.
Used in a sentence, “The human being said what they were trying to sell you was conceptualized and discussed in an office thus the statement is official”.