There are a total of 48 4-letter words containing 'oi', and the number may vary in different dictionaries. You can specify the dictionary and order.

• boil ₈
• bois ₇
• choi ₉
• coif ₁₀
• coil ₈
• coin ₈
• coir ₇
• doit ₅
• foie ₇
• foil ₈
• foin ₈
• joie ₁₃
• join ₁₄
• kois ₈
• loid ₆
• loin ₆
• moil ₈
• moit ₇
• naoi ₅
• noil ₆
• noir ₅
• oick ₁₁
• oiks ₈
• oils ₅
• oily ₇
• oink ₉
• pois ₇
• quoi ₁₄
• roid ₅
• roil ₅
• soie ₄
• soil ₅
• soit ₄
• toil ₅
• toit ₄
• void ₉
• voir ₈
• voix ₁₅
• zoic ₁₆
• coit ₆
• euoi ₄
• foid ₈
• hioi ₇
• hoik ₁₁
• loir ₄
• mooi ₆
• oint ₄
• roin ₄

There are 48 4-letter words containing oi in the well-known word game dictionary, 27 in the Scrabble US (US/Canada/Thailand - TWL/NWL) dictionary, and 38 in the Scrabble UK (International - SOWPODS/CSW) dictionary, and 39 in the Words with Friends (WWF) dictionary.