Definition of "mebbe"

Mebbe the Don wants to pay a sociable call on our ladies. Mebbe his gang is some hungry, as usual.

1914, Zane Grey, The Light of Western Stars

Wal, if a man can stand the loneliness, an' if he's quick on the draw, mebbe lone-wolfin' it is the best.

1915, Zane Grey, The Lone Star Ranger‎

"I thought mebbe there was something wrong at the Willows," he said.

1929, Edith Wharton, Hudson River Bracketed

“Well then, it's Granny speaking: 'I dunnow!Mebbe I'm wrong to take it as I do.There ain't no names quite like the old ones though,Nor never will be to my way of thinking. […]

2013 April 22, Robert Frost, The Road Not Taken and Other Selected Poems (Timeless classic)‎, Simon and Schuster