In a marginal manner, or to a marginal extent; barely sufficiently; slightly(adverb)
In the margin of a book(adverb)
Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License
Use "marginally" in a sentence
"He noted the hybrid Malibu only gets what he described as marginally better fuel economy and said that the price is more expensive."
"He spent two and a half years in the Navy, eventually given a general discharge under honorable conditions, following several minor infractions and an attitude which he describes as marginally insubordinate."
"But if you do, you can have enough respect for the rest of us to actually post a few concise arguments here, not just paste in marginally-to-not-at-all relevant links to long winded arguments you made elsewhere 10 years ago."