Etymology

Allowing for the possibility of erroneous vocalizations in the original Arabic script, the morpheme "قَدْ - Qad" may well occur in "فَدْ - fad", by deleting one of the two dots above "قَ".

Compare with Latin «fidus» - "trusty, trustworthy, dependable, credible, loyal, faithful, certain, steadfast", from Proto-Italian «feiðos» - "faithful, reliable".