“Maverick” is so popular that basketball’s Dallas Mavericks have this word as their nickname. The word “maverick” can be used as a noun or a verb.
 
 
(Oxford English Dictionary)
maverick, n. and a.
[< the name of Samuel Augustus Maverick (1803-70), U.S. politician, and the owner of a large herd of cattle in Texas in which the calves were unbranded.
Cf.:
1869 Overland Monthly Aug. 127/1 One Maverick formerly owned such immense herds that many of his animals unavoidably escaped his rouanne in the spring, were taken up by his neighbors, branded and called ‘mavericks’. The term eventually spread over the whole State, and is in use now, not only to denote a waif thus acquired, but any young animal. No great drove can sweep through this mighty unfenced State without drawing a wake of these ‘mavericks’.
An etymology from the name of a Samuel Maverick resident in Boston in the early 17th cent. has elsewhere been suggested, but seems implausible in view of the date of the earliest examples of the word, and the fact that this Maverick had no connection with cattle farming; evidence is lacking to support the claim that the word is earlier attested denoting an unmarked log in a Maine river drive.] 
A. n.

1. N. Amer. An unbranded calf or yearling.

1867 in J. G. McCoy Hist. Sketches Cattle Trade (1940) 83 The term maverick which was formerly applied to unbranded yearlings is now applied to every calf which can be separated from the mother cow. 1870 J. C. DUVAL

xxviii. 163 A party of five Tonkawa warriors came within half a mile of my ranch, and in broad daylight killed one of my fattest ‘mavericks’. 1887 F. FRANCIS Saddle & Mocassin 172 Nowadays you don’t dare to clap a brand on a mavorick even.
2. U.S. A thing obtained dishonestly. rare.

1890 Cent. Dict., Maverick,..anything dishonestly obtained, as a saddle, mine, or piece of land. (Western U.S.).
3. An unorthodox or independent-minded person; a person who refuses to conform to the views of a particular group or party; an individualist. Also in extended use.

1892 R. KIPLING Life’s Handicap 195 A very muzzy Maverick smote his sergeant on the nose. 1948 Chicago Daily News 11 June 16/7 One Republican Senator, and not by any means a conspicuous maverick, pointed out that the Senate might have acted.
B. adj. That is or derives from a maverick; (chiefly in extended use) individualistic, unorthodox, independent-minded.

1886 Calif. Maverick (San Francisco) 13 Feb. 4/1 People would say, ‘He holds maverick views’, meaning that his views were untainted by partisanship in the matter. 1893 19th Cent. May 791 Ain’t you afeard that ar maverick meat’ll choke you? 1901 McClure’s Mag. Dec. 147 Occasionally they found a maverick legislator, or traded for one.
   
   
8 November 1884, Coshocton (Ohio) Age, pg. 2:
Indians and Mexicans helped themselves to all they desired, and Texas “Mavericked” those that displayed no brand.
 
This word “Maverick” is said to have originated with a certain Irishman by that name who was one of the foremost in adding to his stock by taking all he could find; in some cases it is said he took what belonged to others also; however, the word thereafter was applied to all cattle unbranded that had ceased sucking, as a sucking call rightfully belongs to the owner of the mother, and is branded accordingly.
 
 
26 January 1886, Galveston (TX) Daily News, pg. 4:
The Houston Age adopts without comment the fable that the word maverick, applied to cattle, originated as follows:
 
In the early days Mr. Samuel Maverick, a wealthy San Antonian, had a large stock of cattle and did not have them looked after and marked and branded very closely, and it got to be the case that all the unmarked cattle on the range were called mavericks.
 
This is a fiction. The word was in use a hundred years ago in Louisiana, as appears by the history of Judge Martin.