The fat of the land, say? (6)
I believe the answer is:
grease
'the fat' is the definition.
(animal fat for cooking)
'land say?' is the wordplay.
I cannot quite understand how this works, but
'say?' could be 'as' (I've seen this in other clues) and 'as' is located in the answer.
The remaining letters 'gree' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'of the' is the link.
Can you help me to learn more?
(Other definitions for grease that I've seen before include "Travolta's 1978 film" , "Mechanic (informal)" , "Thick lubricant or frying oil" , "Oily lubricant" , "Musical starring John Travolta and Olivia Newton-John" .)