The letter combinations ouil (at the end of a word) and ouill (almost anywhere*) have no English equivalent: they are pronounced like the oo in "boo" plus a "y" sound. The IPA spelling is [uj], and the Lawless phonetic spelling is [uy].
Do not pronounce this like the word oui:
[wi]. It helps to look at the letter combination as ou + il, rather than as oui + l. (The sound [wij] is spelled UIL after a consonant.)