Arsénio Martins Lafuente Nunes (born 30 August 1989), known simply as Arsénio, is a Portuguese footballer who plays for Moreirense F.C. as a winger.
Born in Esposende, Braga District, Arsénio began playing football with local AD Esposende, signing with FC Porto at the age of 12 and completing his formation with Leixões SC. He spent his first four years as a senior in the lower leagues, with Padroense FC, C.S. Marítimo B and G.D. Ribeirão.
Arsénio signed with C.F. Os Belenenses in the 2012 summer, playing his first match as a professional on 11 August and scoring once in a 3–1 home win against C.D. Feirense for the Segunda Liga championship. He contributed with 42 games and five goals during the season, helping the Lisbon club return to the Primeira Liga after three years.
Arsénio made his debut in the top level on 18 August 2013, coming on as a 46th-minute substitute in a 0–3 loss to Rio Ave FC. In the following transfer window, he was loaned to Moreirense F.C. in division two, scoring three times to help his team achieve promotion as champions; subsequently, the move was made permanent for two years.
On 18 June 2015, Arsénio joined Bulgarian side PFC Litex Lovech. His first competitive appearance took place on 2 July, as he featured 77 minutes in a 1–1 draw at FK Jelgava for the first qualifying round of the UEFA Europa League. He netted his first goal in the league late in that month, helping his team to a 2–2 away draw against PFC Levski Sofia.
On 1 July 2017, Arsénio returned to Portugal, its top division and Moreirense by signing a two-year contract.