SLUMBEROUS Meaning of SLUMBEROUS in English [slum.ber.ous] or slum.brous adj (15c) 1: heavy with sleep: sleepy 2: inducing slumber: soporific 3: marked by or suggestive of a state of sleep or lethargy "a ~ state of peace" Merriam-Webster English vocab. Английский словарь Merriam Webster. 2012