Tûk is the Actual Westron spelling, also spelled Tûc in a draft (from Peoples of Middle-earth). Its spelling is "Englished" as "Took":
"Took. Hobbit-name of unknown origin representing actual Hobbit Tûk (see III 415). It should thus be kept and spelt phonetically according to the language of translation."
--From Tolkien's "Guide to Names"
The real world surname:
"Took" is an actual surname of England. Took, along with other hobbit surnames, such as Maggot, are featured in The Dictionary of English and Welsh Surnames*, published in 1901. Since it is the chief reference work in that field, Tolkien was likely aware of this resource. Perhaps he even looked through this book to pick out suitable hobbit family names.
Unlike most of the other names, the entry for "Took" gives no suggested meaning or etymology.
*Available as a free e-book here.
A Norse simpleton:
However, philologists suggest that the etymology of the name may be Old Norse Tóki, meaning "simpleton". This is fitting for a "Fool of a Took!"
There has been debate about how to correctly pronounce the name. I wondered how the real-world Took family name is pronounced: with a "long OO" (as in "spook") or a "short OO" (as in "book")?
Even though the Actual Westron pronunciation would be with a "long OO", if the real Took name is pronounced with a "short OO", then the "English translation" of the name would be with a short OO too. Such a change in pronunciation is precedented, such as Actual Westron Bophîn ("Boff-een") to Englished Boffin ("Boff-inn").
So I decided to find out.
There is a British comedian named Barry Took. I have chatted with an English person, who said the name was pronounced like "book". (If I'm mistaken, feel free to chime in.)
This means the Englished pronunciation of Took would be like "book", though the Actual Westron name Tûk would rhyme with "spook".
The meaning of "Took"...a wholly unfounded guess?:
In Peoples of Middle-earth, JRRT says that according to the family tradition of the Tooks, the word tûca "was an old word meaning 'daring', but this appears to be a wholly unfounded guess"
Again, the implication is that since the meaning was an "unfounded guess", JRRT chose to not translate the name. It's a little funny that the name probably means "fool" instead of "daring"; the latter meaning is way for the clan to salvage their pride.
A Daring, Rash, and Bold Took:
But, if this "unfounded" meaning were to be translated into English, there are three words which would match:
A) "Daring" or "Dare". Dare is a real-world English surname, such as Virginia Dare, the first child born in English America.
Tolkien's foolhardy side:
In a letter, Tolkien gives the etymology of his family name:
"My name is TOLKIEN (not -kein). It is a German name (from Saxony), an anglicization of Tollkiehn, i.e. tollkühn. But, except as a guide to spelling, this fact is as fallacious as all facts in the raw. For I am neither 'foolhardy' nor German"
The German word tollkühn simply means "foolhardy, daredevil". (Link to wiktionary entry.) The cognate in English would be "dull-keen".
Note that the Tooks are the most bold and adventurous branch of the hobbits, and that the daring aspect of Bilbo's personality is attributed to his partly Tookish ancestry. And Peregrin Took is the "fool" of the Fellowship.
A slender jest: Took, Rashbold, and Tolkien:
In JRRT's time-travel story, The Notion Club Papers, the Notion Club is a fictional version of the Inklings. In this Club, there is a member named Professor Rashbold. His son is also a participant in the Club. Despite Christopher Tolkien's disavowal, to some degree, the two Rashbolds are surely a fictive depiction of Professor Tolkien and his son Christopher.
And so I suggest there is a "slender jest" by Tolkien when he coyly refused to definitely say what the name Took meant. Why? Because the name is supposed to be a punny reference to his own family name.
Just as "Rashbold" is an alter ego of Tolkien in the Notion Club Papers, so is "Took" an alter ego of Tolkien in the Shire...embodying only his "foolhardy" aspect.
Perhaps few outside of his family and fellow Inklings would notice such a slender jest.
Boffins: nouveau riche hobbits or a nerdy hobbits?
A couple notes on the name "Boffin":
Tolkien might've originally used the name Boffin (in The Hobbit and Mr. Bliss) as a nod to the newly-rich family of Boffins, from a Charles Dickens novel: http://en.wikipedia.org/wiki/Boffin
By WWII, the name was British slang for a "mad scientist" or "nerd". Perhaps Falco Boffin, who helps Frodo leave the Shire, was a "nerdy" fellow.