Fat cat a wealthy and powerful person, especially a businessman or politician; the term is recorded from the late 1920s in the US, but has become frequent in the UK since the early 1990s, in relation particularly to what are perceived as inflated salaries paid to senior executives of formerly nationalized industries.
the fat is in the fire something has been said or done that is about to cause trouble or anger. In this current sense with reference to the sizzling and spitting resulting from a spillage of cooking fat into an open flame. The expression is recorded from the mid 16th century in the sense that something has gone irretrievably wrong.
the fat of the land the best of everything as one's resource for living; originally with reference to Genesis 45:18, ‘Ye shall eat the fat of the land.’
see also a green Yule makes a fat churchyard, the opera isn't over till the fat lady sings.