imperceptibly (adverb) imperceptibly: slowly
Sinonime: bottomward, cascading, declining,
depressed, descending, downgrade, downhill, downward, dropping, earthward, falling, gravitating, groundward,
inferior, nether, precipitating, sagging, sinking, sliding, slipping, slumping, subjacent, to the bottom,
under, underneath
Antonime: above,
higher