score:4
In Mario Cassar, The surnames of the Maltese Islands: an etymological dictionary (2003):
APAP
(1) Greek — nickname (?); < Gk. Apapis [De Soldanis], < apapy, a dandelion-like weed; of uncertain application as a surname. The surname Avap (a possible cogante form) prevails in Italy.
(2) Arabic — nickname; tautological form of Ar. ab meaning “father” [Mikiel Anton Vassalli: Lexicon, 1796], in which case the aggregate term term might suggest “grandfather, ancestor” [MG]. The surname Ap also prevails in Italy.
Old local forms: Hapap. (De) Apapis
The surname Apap features neither in the Militia List of 1419/20 nor in the Angara Roster of the 1480’s, but figures prominently in the Gozitan Crociata Records of 1533 [Wettinger:1980]. Probably, up till then it was still confined to Gozo; landowner Aloisio Apap is recorded there in 1502 [De Soldanis]. The Apap family erected (or acquired) the beneficies of Ta Caddiesa (1502), Habel Don Lorenzo (1509), and Ta Ghammar (1576) [Montalto]. (1509), and Ta Ghammar (1576) [Montalto]. The Apaps were one of the prominent landed gentries of Gozo who survived the Moorish onslaught of 1551 [MG]. Don Lorenzo De Apapis (1501-1586), parish priest of St George's in Rabbato, was actually taken into captivity, only to be redeemed soon after the event [Mifsud-Bonnici]; another priest, Antonius Hapap, is recorded in Gozo in 1510 [Wettinger: 2002], In 1712 Filippo Apap was created Marquis of Ġnien is-Sultan by Grand Master De Rohan [Montalto].
- Several Jews bear the praenomen Aba meaning “forefather, ancestor”; Gk. papas also means “father”, a title of respect used in addressing a parish priest of the Orthodox Church.
EDIT: I've given this some thought overnight, and there are still some things from Cassar's entry that need clarification: