plug away vs keep one's nose to the grindstone

plug away and keep one's nose to the grindstone both are verbs.

Word	Noun	Adjective	Verb	Adverb
plug away	No	No	Yes	No
keep one's nose to the grindstone	No	No	Yes	No

As verbs, plug away and keep one's nose to the grindstone are synonyms defined as:

plug away and keep one's nose to the grindstone: work doggedly or persistently

Other synonyms of plug away include keep one's shoulder to the wheel, peg away, slog.

plug away (verb)	keep one's nose to the grindstone (verb)
persist in working hard	work doggedly or persistently
work doggedly or persistently