There aren’t a lot of Irish words in English, but there are some. See for instance, slew and slogan.
Dennis King has created “In Dúil Bélrai“, an antique term for a glossary. In this case, a new English – Old Irish glossary in the form of a searchable database, with over 5,000 Old and Middle Irish words, with a little Early Modern Irish mixed in. Dennis King writes to the Old Irish List “We’re still tinkering with it and adding new vocabulary, but we invite you all to give it a try.”