Squarish
/ˈskwerɪʃ/
Definition 1 of 1
Pro Tip 1/3Physical Comparison
Use 'squarish' to compare objects or features to a near square shape. 
He lives in a squarish apartment.
Pro Tip 2/3Imprecise Shape
'Squarish' suggests a shape is not a perfect square but close. 
The plot of land we bought is squarish but not exactly square.
Pro Tip 3/3Non-Technical Use
'Squarish' is suited for everyday language, rather than precise mathematical contexts. 
I would describe that table as squarish.