Yeehaw (Yee-ha; Yee-haw)

“Yeehaw” (or “yeeh-ha” pr “yee-haw”) is similar to the yell “yahoo!” It indicates excitement, exuberance, and delight. “Yee-haw!” is imitative of the bray of a donkey.
       
“Cowboys go ‘yee haw’ and ninjas go ‘hee yaw‘“ is a related saying.
   
     
Urban Dictionary
yee haw 
1. What a cowboy or redneck might say; equivalent to the urban “Yeah!” or “Woo!”.
2. A stupid redneck.
1. Yee haw! Boy howdy!
2. Look at that yee haw blowing into his jug and dancing like a monkey.
by SC.Zee Apr 1, 2004
   
yee haw 
A non descript exclamation which usually accompanies alot of hooting and whistling at whatever is causing the excitement. Most likely coined in the southern states of north America (eg Texas). Can also be used to punctuate traditional country and western music.
It might also be exclaimed by the rider of a bull or bucking bronco at a rodeo or their spectators.
Whilst at the rodeo the rider of the bucking bronco yelled;
“YEEEEE HAWWWWWW!”
by Dacarlo Apr 8, 2004
   
Cowboy Lyrics
Artist/Band: Owen Jake
Lyrics for Song: Yee Haw
Lyrics for Album: Startin With Me
 
It’s five o’clock, just got paid:
I’ll be off the next two days.
No more workin’ like dogs,
No more leash, no more boss.
I’ve got a weekend of nothin’ to do at all:
Yee Haw!
 
I know a place down the road,
The girls are hot, the beer is cold.
It’s two-for-one, yeah, that’s right:
Not just drinks; it’s girls to guys.
I hear the twins are back in town from Saginaw:
Yee Haw!
 
You take your all-right; you take your can’t-wait.
A lotta of bring-it-on an’ some damn straight,
An’ mix it all up with some down home southern drawl, y’all:
You got your yee haw!   
     
Internet Movie Database
Plot summary for
My Darling Clementine (1946)
“My Darling Clementine” is John Ford’s retelling of the Earp/Clanton fued, and the famous show down at the OK Corral. Ford embellishes on the story by centering the plot on the fictional character Clementine (Doc Holliday’s schoolteacher flame from back east). Written by Jeff Walker {pasingphas@yahoo.com}
     
Script-O-Rama
My Darling Clementine Script - Dialogue Transcript
                       
[Singing Continues]   
Yee-ha!
[Yipping]       
Yee-ha! Ya-hoo!   
Yee, yippa-hoo! Yeah-ha!
     
(Oxford English Dictionary) 
yeehaw, int.
Chiefly U.S
[Imitative. Cf. YAHOO int.] 
An exclamation of enthusiasm or exuberance; ‘yahoo!’
[1929 N.Y. Times 24 Mar. 5/8 The old ballads had a feeling not found in ‘mammy’ songs… They seemed to have possessed something more than derives from the efforts of the strident lads whose ‘m-a-m-m-ys’ yee-haw upon a stricken and helpless world.] 1941 Jrnl. Negro Educ. 10 83 He lets go. ‘Yee-hoo-oo-o!’ George says, and all for the freedom.
   
7 September 1844, Milwaukie (WI) Sentinel, pg. 3, col. 3:
As a well dressed lady was proceeding down Third Avenue, on Wednesday, a huge jackass was observed to throw up his nose etc.—Presently he kicked up his heels, and with a most sonorous yee-haw! yee-haw! set off at the top of his speed down the avenue.
       
8 May 1875, Dallas (TX) Weekly Herald, pg. 1:
[From the Rochester Democrat.]
(...)
Then of all the pullin’ and haulin’ and sweatin’ and gruntin’ and tuggin’ and liftin’ and yeehawin’ you ever seen or heard of, we yeehawed.
 
Google Books
Lutchmee and Dillio: a study of West Indian Life
by Edward Jenkins
London: W. Mullan & Son
1877
in three volumes
Volume II
Pg. 12:
Yee-ha!—oh ha!
Who see de niggah?
Yo ha!—yee ha!
Where go de niggah?
Singing for Jee-roo-sa-lem,
Chorus:
Singing for Jee-roo-
Singing for Jee-roo-
Singing for Jee-roo-sa-lem!
 
Google Books
The Snake-dance of the Moquis of Arizona
by John Gregory Bourke
New York: Scribner
1884
Pg. 161:
“This was repeated eight or ten times, all singing a refrain, keeping time by stamping vigorously with the right foot: ‘Oh-ye-haw, oh-ye-haw, ha-yee-ha-ha-yee-ha-ha-yi-ha-a-a-a,’ chanted a dozen tomes or more with a slow measure and graceful cadence.”
 
1 May 1902, Des Moines (Iowa) Daily Leader, pg. 7, col. 6:
A donkey can put a great deal of pathos into its yeehaw! yeehaw!
 
15 July 1906, Washington Post, pg. 8 ad:
LUNA PARK
YEE HAW! YEE HAW! YEE HAW!
THE ORIGINAL MAUD,
THE MULE THAT CAN’T BE RIDDEN
 
6 August 1943, Sheboygan (WI) Press, pg. 7, col. 5:
Similar to the bray of a mule is the “yee haw” yell of Marine parachutists who “give” when they dive from the plane into space.