What is the difference between: "قد" and "ربما" (qad and rubbamā), "فرنسي" and "فرنساوي" (faransī and faransāwī), "غزي" and "غزاوي" (ghazzī and ghazzāwī), "سمائي" and "سماوي" (samā’ī and samāwī)? And what is the nisba for "بيرو" (Peru) and "أفغانستان" (Afghanistan)? And why?

"Qad" (قد) and "rubbama" (ربما) are used for lessening, and "qad" may also come with other meanings such as expectation and realization. "Rubb" (رب) may be used for both increase and decrease. "Samā’ī" (سمائي) and "samāwī" (سماوي) have the same meaning and both are correct. "Faransī" (فرنسي) is grammatically correct when attributing to France. "Ghazzī" (غزي) is more correct for attributing to Gaza, while "Ghazzāwī" (غزاوي) is attributed to the colloquial pronunciation. The attribution to Afghanistan is "Afghanī" (أفغاني). For attribution to "Peru," both "Bīrūwī" (بيروي) or "Bīrī" (بيري) are permissible.