to cause (something) to be or appear less
to reduce (a person or thing) in standing or perceived worth
Any man's death diminishes me — John Donne
in architecture, to make (something) taper
in music, to decrease (an interval) by a semitone
to become gradually less; to dwindle
to taper
diminishable adj
[Middle English deminishen via French from late Latin diminuere, alteration of Latin deminuere, from de- + minuere to lessen]