to cause to separate and go in different directions
"Dissipate" also means "spend frivolously and unwisely"--this definition does not fit the example sentence, but it will soon be a rare action in the lives of the Joads, and it was used in an introductory description of the author Steinbeck: "His work demanded his attention so fully that he finally refused to dissipate his energy in extra-literary pursuits."
In the last part of May the sky grew pale and the clouds that had hung in high puffs for so long in the spring were dissipated.
The use of the adverb "cunningly" to describe the wind personifies it as a clever villain that fights with the corn by digging and uprooting so that it could only accuse its murderer with the position of its fallen body.
During a night the wind raced faster over the land, dug cunningly among the rootlets of the corn, and the corn fought the wind with its weakened leaves until the roots were freed by the prying wind and then each stalk settled wearily sideways toward the earth and pointed the direction of the wind.
"Snub" is used as an adjective here, but as a verb, it means "refuse to acknowledge" or "reject outright and bluntly" and as a noun, it means "an instance of driving away and warding off"--all these definitions also fit how the tractors and drivers interact with the tenant farmers who are being plowed out of their land and house.
Snub-nosed monsters, raising the dust and sticking their snouts into it, straight down the country, across the country, through fences, through dooryards, in and out of gullies in straight lines.
"Petulant" means "easily irritated or annoyed" and "scowl" means "frown with displeasure"--these two words describe the truculent look of Muley, whose name is also indicative of his mood ("mulish" means "unreasonably rigid in the face of argument or entreaty or attack").
Muley’s face was smooth and unwrinkled, but it wore the truculent look of a bad child, the mouth held tight and small, the little eyes half scowling, half petulant.
A large red drop of sun lingered on the horizon and then dripped over and was gone, and the sky was brilliant over the spot where it had gone, and a torn cloud, like a bloody rag, hung over the spot of its going.
Two rangy shepherd dogs trotted up pleasantly, until they caught the scent of strangers, and then they backed cautiously away, watchful, their tails moving slowly and tentatively in the air, but their eyes and noses quick for animosity or danger.