The difference between Stain and Sully

When used as nouns, stain means a discoloured spot or area, whereas sully means a blemish.

When used as verbs, stain means to discolour, whereas sully means to soil or stain.

check bellow for the other definitions of Stain and Sully

Stain as a noun:

A discoloured spot or area.
Stain as a noun:

A blemish on one's character or reputation.
Stain as a noun:

A substance used to soak into a surface and colour it.
Stain as a noun:

A reagent or dye used to stain microscope specimens so as to make some structures visible.
Stain as a noun (heraldry):

Any of a number of non-standard tinctures used in modern heraldry.

Stain as a verb (transitive):

To discolour.

Examples:

"to stain the hand with dye"

"armour stained with blood"
Stain as a verb:

To taint or tarnish someone's character or reputation
Stain as a verb:

To coat a surface with a stain

Examples:

"to stain wood with acids, coloured washes, paint rubbed in, etc."

"the stained glass used for church windows"
Stain as a verb (intransitive):

To become stained; to take a stain.
Stain as a verb (transitive, cytology):

To treat (a microscopic specimen) with a dye, especially one that dyes specific features
Stain as a verb:

To cause to seem inferior or soiled by comparison.

Sully as a verb (transitive):

To soil or stain; to dirty.

Examples:

"synonyms sowq1=obsolete"

"He did not wish to sully his hands with gardening."
Sully as a verb (transitive):

To corrupt or damage.

Examples:

"She tried to sully her rival’s reputation with a suggestive comment."
Sully as a verb (intransitive):

To become soiled or tarnished.