i SUFFIX
art or craft done by the person (abstract noun of person); office of, -ship;
tenebri.um N 1 1 GEN P F uncommon
tenebra, tenebrae N (1st) F [XXXAX]
darkness (pl.), obscurity; night; dark corner; ignorance; concealment; gloom;
i SUFFIX
makes abstract noun of the verb; place/instrument/result of verb action;
tenebri.um N 2 2 NOM S N
tenebri.um N 2 2 VOC S N
tenebri.um N 2 2 ACC S N
tenebri.um N 2 2 GEN P N uncommon
tenebro, tenebrare, tenebravi, tenebratus V (1st) [EXXES] Later uncommon
darken, make dark;

Credits:
This, our local install of the popular standby Whitaker's Words, is possible thanks to the resurrection of the venerable project at William Whitaker's Words, where you will also find extensive documentation. The corresponding GitHub repository is where you can submit issues about missing forms and analyses.
This web interface by Walter M. Shandruk.