Lexicographers define words based on how speakers actually use them in print, not on how authorities say they should be used; the dictionary is a record of the language, not a referee of it. This means offensive, illogical, or 'incorrect' usages get entries once they appear widely enough in edited prose.
Stamper spent roughly a month revising the entry for the small common word 'take,' which carries dozens of distinct senses and idiomatic uses, far longer than rare technical terms require. The most ordinary words are the hardest to define because their meanings are so numerous, blurred, and intuitively obvious that forcing them into discrete senses is grueling.
Lexicographers practice a disciplined attention called 'reading and marking,' scanning ordinary texts for words used in novel ways and logging each on a citation slip. Definitions are then built only from an accumulated pile of real citations, so no sense enters a dictionary until usage evidence physically exists to support it.
A dictionary's clean numbered senses are an artificial grid imposed on meanings that in reality bleed into one another along a continuum. Defining is less discovery than negotiation: deciding where one sense stops and another begins is a judgment call, not a fact waiting to be found.
A good definition can be slotted back into a real sentence in place of the word and preserve the meaning, which forces definers to match the word's part of speech and grammatical behavior. This constraint makes definition-writing a mechanical discipline of fit rather than free paraphrase.