Significant weight (4)
(Other definitions for heft that I've seen before include "Lift or hold something to assess its weight" , "Lift (something heavy)" , "Lift in order to heave, say an axe" , "Try to determine weight by lifting" , "Feel the weight of" .)
(Other definitions for ton that I've seen before include "2240lbs" , "Unit of weight equivalent to 2240 pounds" , "A slangy 100 mph - heavy" , "Heavy weight or 100mph" , "U nit of weight" .)