Cuisneoir is a masculine noun that means fridge.
It is lenited here, following the official written standard, because of the preceding sa (in the).
In spoken Munster and Ulster Irish, sa usually lenites, when followed by a lenitable consonant (although there are specific cases in spoken Munster Irish where it produces eclipsis).
In spoken Connacht Irish, sa never lenites but eclipses, when followed by an ecliptable consonant: sa gcuisneoir (in the fridge), sa mbád (in the boat), sa ngleann (in the valley) ⁊rl…