From Wiktionary, the free dictionary
Maybe from Ashokan Prakrit *𑀩𑀸𑀧𑁆𑀧 (*bāppa) but probably from Arabic بَابَا (bābā).
ബാപ്പ • (bāppa)
- father; mostly used by Muslims.
- Synonym: അപ്പൻ (appaṉ)
- Warrier, M. I. (2008) “ബാപ്പ”, in Malayalam-English Dictionary (in Malayalam), 22nd edition, Kottayam: DC Books