This character is a Other Letter and is mainly used in the Arabic script.
The glyph is not a composition. It has no designated width in East Asian texts. In bidirectional text it is written as Arabic letter from right to left. When changing direction it is not mirrored. The word that U+0648 forms with similar adjacent characters prevents a line break inside it. The glyph can be confused with 39 other glyphs.
The Wikipedia has the following information about this codepoint:
Waw (wāw "hook") is the sixth letter of the Semitic abjads, including
Phoenician wāw 𐤅,
Aramaic waw 𐡅,
Hebrew vav ו,
Syriac waw ܘ
and Arabic wāw و (sixth in abjadi order; 27th in modern Arabic order).
It represents the consonant [w] in classical Hebrew, and [v] in modern Hebrew, as well as the vowels [u] and [o]. In text with niqqud, a dot is added to the left or on top of the letter to indicate, respectively, the two vowel pronunciations.
It is the origin of Greek Ϝ (digamma) and Υ (upsilon), Cyrillic У, Latin F and V and later Y, and the derived Latin- or Roman-alphabet letters U and W.