Muhammad (Arabic: محمد) is the primary transliteration of the Arabic given name مُحَمَّد that comes from the passive participle of the Arabic verb ḥammada (حَمَّدَ), praise, which comes from the triconsonantal root Ḥ-M-D. The word can therefore be translated as "praised, commendable, laudable".
Sinan (Arabic: سنان ‎‎) is a word found in Arabic and Early Arabic, meaning spearhead. The name might also be related to the Ancient Greek name Sinon. It was subsequently used as a male given name.
1) Spear in Arabic is NOT Sinan. It is "Romh" Ø±Ù…Ø 2) 'Spearhead' in Arabic is called "Sin" - a synonym of "tooth". The plural 'spearheads' would therefore become "Asnaan" (as corresponding for the word for 'teeth'), not Sinan. 3) Sinan Bin Thabit was perhaps the first person who had the name Sinan.