The difference between Casual and Unexpected

When used as adjectives, casual means happening by chance, whereas unexpected means not expected, anticipated or foreseen.

Casual is also noun with the meaning: a worker who is only working for a company occasionally, not as its permanent employee.

check bellow for the other definitions of Casual and Unexpected

Casual as an adjective:

Happening by chance.

Examples:

"They only had casual meetings."
Casual as an adjective:

Coming without regularity; occasional or incidental.

Examples:

"The purchase of donuts was just a casual expense."
Casual as an adjective:

Employed irregularly.

Examples:

"He was just a casual worker."
Casual as an adjective:

Careless.
Casual as an adjective:

Happening or coming to pass without design.
Casual as an adjective:

Informal, relaxed.
Casual as an adjective:

Designed for informal or everyday use.

Casual as a noun (British, Australian, NZ):

A worker who is only working for a company occasionally, not as its permanent employee.
Casual as a noun:

A soldier temporarily at a place of duty, usually en route to another place of duty.
Casual as a noun (UK):

A member of a group of football hooligans who wear expensive designer clothing to avoid police attention; see .
Casual as a noun:

One who receives relief for a night in a parish to which he does not belong; a vagrant.
Casual as a noun (video games, informal, derogatory):

A player of casual games.

Examples:

"usex The devs dumbed the game down so the casuals could enjoy it."
Casual as a noun (British):

(dated) A tramp.