Latin suffixes -or and -idus, is there a correspondence?

Question

In Latin (and daughter languages), there seems to be a correspondence between nouns of the third declension in -or/-us, -oris denoting a quality, and adjectives of the Ist class in -idus,a,um denoting something or someone possessing the corresponding quality (sometimes approximately, I guess out of semantic drift).

Here are the ones that I could find in Italian (some in Latin). I'm sure there are more, but these are already many enough to suggest a pattern:

• CALOR, CALIDUS (Latin)

• FRIGUS, FRIGIDUS (Latin)

• HUMOR (as in liquid), HUMIDUS (Latin)

• AMOR (as in cohesion), AMIDUS (Latin)

• timore, timido (Italian)

• pavore, pavido

• pallore, pallido

• candore, candido

• squallore, squallido

• valore, valido

• fetore, fetido

• sapore, sapido

• tumore, tumido

So, what is the pattern, and how did it originate? Is this appearing also in other IE languages?

Answer 1

According to Wiktionary, -idus is "suffix forming adjectives", but most of the words in the Category:Latin words suffixed with -idus, are based on a verb.

-or is similarly "used to form a third-declension masculine abstract noun from a verb root or conceived root form"

So the relationship is that these are morphemes commonly used to form an adjective and an abstract noun respectively from a (usually verbal) root.