The difference between Gnast and Spark

Gnast as a noun (obsolete):

A spark; a dying or dead spark, as of a snuffed candle.

Gnast as a verb (ambitransitive, obsolete):

To gnash.

Spark as a noun:

A small particle of glowing matter, either molten or on fire.

Spark as a noun:

A short or small burst of electrical discharge.

Spark as a noun:

A small, shining body, or transient light; a sparkle.

Spark as a noun (figuratively):

A small amount of something, such as an idea or romantic affection, that has the potential to become something greater, just as a spark can start a fire.

Spark as a noun:

(in plural sparks but treated as a singular) A ship's radio operator.

Spark as a noun (UK, slang):

An electrician.

Spark as a verb (transitive, figurative):

To trigger, kindle into activity (an argument, etc).

Spark as a verb (transitive):

To light; to kindle.

Spark as a verb (intransitive):

To give off a spark or sparks.

Spark as a noun:

A gallant, a foppish young man.

Spark as a noun:

A beau, lover.

Spark as a verb (intransitive):

To woo, court; to act the gallant or beau.