RhymeZone: undertime definitions

Definitions of undertime:

verb: (transitive) To measure wrongly, so that it seems to take less time than actually required.
verb: (transitive, photography) To underexpose.
noun: (informal) The time spent at a workplace doing non-work activities.
noun: (obsolete) The later part of the day; afternoon; undertide.

(Definitions from Wiktionary)