insurgendum

• (Classical) IPA^(key): /in.surˈɡen.dum/, [ĩːs̠ʊrˈɡɛn̪d̪ʊ̃ˑ]
• (modern Italianate Ecclesiastical) IPA^(key): /in.surˈd͡ʒen.dum/, [insurˈd͡ʒɛn̪d̪um]

From īnsurgō (“I rise up [against]”).

īnsurgendum (accusative, gerundive īnsurgendus)

1. rising up
   • 1637, Johannes Clüver, “Epitomes…Appendix: Res ab anno hujus ſeculi xxx. uſque in hunc xxxiii. geſtas continens”, in Hiſtoriarum Totius Mundi Epitome, page 17:

     In hunc totis caſtris inſurgendum videns Tillius Comes, partem equitulus præmittit, ſubſequitur ipſe cum firmiſſimo exercitu.

     Seeing this uprising in the whole camp, the young knight, Count Tilly, sends ahead a contingent, and himself follows close after with the most steadfast of the army.

Second declension, defective.

There is no nominative form. The present active infinitive of the parent verb is used in situations that require a nominative form.
The accusative may also be substituted by the infinitive in this way.

Regularly declined forms of īnsurgendus (“which is to be risen up [against]”).

īnsurgendum

1. inflection of īnsurgendus:
   1. nominative/accusative/vocative neuter singular
   2. accusative masculine singular