aran (“king”) + pant (“full”) #The assimilation of n+p > ph could be “internal nasal mutation”.
Sindarin
araphant
masculine name. Araphant
Elements
Word Gloss aran “king, lord, chief, (lit.) high or noble person, king, lord, chief, (lit.) high or noble person; [N.] lord (of a specific region)” pant “full, full; [G.] (with article) the whole, all the”
Araphant
noun. full king, king of all
The 14th king of Arthedain (LotR/1038). The initial element of his name may be aran “king” and its final element might be the nasal mutation phant of pant “full” (as suggested by David Salo, GS/341).