'Nick' is another word for Prison [UK]
Jail is a word for spending more than a year in police custody. Prison is a word for spending less than a year in police custody. So jail could be another word for prison, although it is not exactly prison.
Jail or gaol
jail
Either you need a word that's not English or the starting letter is wrong. There are many words for prison, but the ones with four letters is jail, brig, or the slang stir.
jail
Inmate.
Are you sure it ends in S? I am thinking jail, but if it ends in S it could be mess, pens, cans.
brig
Gaol
An informal word for a prison that starts with 's' is slammer.During World War II, a German POW prison was called a stalag.
Prison
Envy Is A 4-Letter Word
Jail, gaol and brig (Nautical)
4 letter word for drum is "Dhol".