Iontach resource!
You can search it online or get the app!
Welcome to Foras na Gaeilge’s New English-Irish Dictionary, launched in 2013. The dictionary is available free of charge, and has been adapted to work both on desktop computers and on mobile devices.
As well as translations for the English content, the dictionary also contains grammatical information and sound files. For more information on these latter items, and for instructional videos, see FAQ How do I look up grammatical data? and FAQ How do I listen to sound files? respectively.