A table some say is too long! (4)
I believe the answer is:
mesa
'a table' is the definition.
(synonyms)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for mesa that I've seen before include "US steep-sided tableland" , "In the US south-west, a steep-sided flat-topped hill" , "Flat tableland with steep sides" , "Flat tableland with steep edges" , "Flat hill" .)