French

Verb

approfondir

1. to deepen
2. to consider more thoroughly, to delve deeper into
   • 1837, Louis Viardot, L’Ingénieux Hidalgo Don Quichotte de la Manche^{fr.Wikisource}, translation of El ingenioso hidalgo Don Quijote de la Mancha by Miguel de Cervantes Saavedra, Chapter I:

     Avec ces propos et d’autres semblables, le pauvre gentilhomme perdait le jugement. Il passait les nuits et se donnait la torture pour les comprendre, pour les approfondir, pour leur tirer le sens des entrailles, ce qu’Aristote lui-même n’aurait pu faire, s’il fût ressuscité tout exprès pour cela.

     With these passages and other similar ones, the poor gentleman lost his judgement. He spent his nights and tortured himself to understand them, to consider them more deeply, to take from them their deepest meaning, which Aristotle himself would not have been able to do, had he been resurrected for that very purpose.

Conjugation

This is a regular verb of the second conjugation, like finir, choisir, and most other verbs with infinitives ending in -ir. One salient feature of this conjugation is the repeated appearance of the infix -iss-.