1 decrease, decline, abate, lessen, reduce, lower, shrink, curtail, contract, lop, crop, dock, clip, prune, cut, truncate, cut down, abbreviate, shorten, abridge, compress, condense, pare (down), scale down, boil down:
As the height increases, the pressure diminishes. The need for police patrols was diminished when we hired security guards.
2 belittle, disparage, degrade, downgrade, discredit, detract (from), vitiate, debase, deprecate, demean, derogate, depreciate, vilipend, devalue, cheapen, put down, dismiss, humiliate, demean, reject:
His abuse by the authorities did not diminish him in her eyes.
3 wane, fade, dwindle, ebb, die out or away, peter out, recede, subside; slacken, let up, wind down, slow (down), ease (off), Colloq run out of steam:
Soaking in the hot water, I felt the tensions of mind and body gradually diminishing. The campaign finally diminished to a negligible effort.