Formed vs unformed: charity is external improper form making faith meritorious
The usual Roman School distinction is formed versus unformed faith: unformed is faith alone without charity; formed is faith joined to charity and love.
Charity is called faith's form — not an internal form that constitutes its essence, but an external, improper form that gives faith a relative standing: it profits to eternal life and is, they say, meritorious of salvation.
Latin
IV. Eodem redit distinctio in Scholis Romanis plurimum usitata, per quam fidem distinguunt in formatam atque informem. Nam fidem informem vocant illam quae sola est & sine charitate, fidem vero formatam illam quae est cum charitate & dilectione conjuncta. Docent enim charitatem esse fidei formam, non quidem internam & proprie dictam, quae fidei absolute & in se consideratae essentiam constituat; sed formam quandam externam & improprie dictam, quae esse quoddam externum & respectivum fidei tribuit; nempe quod prosit ad vitam aeternam, & sit, ut loquuntur, salutis meritoria.