The difference between Fall apart and Separate

When used as verbs, fall apart means to disintegrate, whereas separate means to divide (a thing) into separate parts.

Separate is also noun with the meaning: anything that is sold by itself, especially an article of clothing.

Separate is also adjective with the meaning: apart from (the rest).

check bellow for the other definitions of Fall apart and Separate

Fall apart as a verb (intransitive):

To disintegrate.

Examples:

"My old briefcase is falling apart. I'll have to buy a new one."
Fall apart as a verb (idiomatic):

To be emotionally in crisis.

Examples:

"As a result of being addicted to heroin, she was falling apart."

Separate as an adjective:

Apart from (the rest); not connected to or attached to (anything else).

Examples:

"This chair can be disassembled into five separate pieces."
Separate as an adjective (followed by “from”):

Not together (with); not united (to).

Examples:

"I try to keep my personal life separate from work."

Separate as a verb (transitive):

To divide (a thing) into separate parts.

Examples:

"'Separate the articles from the headings."
Separate as a verb:

To disunite something from one thing; To disconnect.
Separate as a verb (transitive):

To cause (things or people) to be separate.

Examples:

"If the kids get too noisy, separate them for a few minutes."
Separate as a verb (intransitive):

To divide itself into separate pieces or substances.

Examples:

"The sauce will separate if you don't keep stirring."
Separate as a verb (obsolete):

To set apart; to select from among others, as for a special use or service.

Separate as a noun (usually, in the plural):

Anything that is sold by itself, especially an article of clothing.