"-ent" is the ending of the third person plural of verbs in the present; the suffix that concerns you is "-ment"; there are in fact two such suffixes and at least one variant of one of them (-ement).

cf. TLFi:

1. Suff. formateur de subst. masc. à partir d’un rad. verbal et parfois d’un adj. ou d’un subst.
2. Suff. formateur de nombreux adv., à partir d’adj. le plus souvent.

Not all verbs, adjectives have a corresponding word in -ment, though.

Examples

charger/chargement, changer/changement, placer/placement,…

lent/lentement, fin/finement, long/longuement, plein/pleinement,… rapide/rapidement