soulful adj.

"A substantial entity believed to be that in each person which lives, feels, thinks, and wills" [Century Dictionary], Middle English soule, from Old English sawol "spiritual and emotional part of a person, animate existence; life, living being," from Proto-Germanic *saiwalō (source also of Old Saxon seola, Old Norse sala, Old Frisian sele, Middle Dutch siele, Dutch ziel, Old High German seula, German Seele, Gothic saiwala), a word of uncertain origin.

It has been suspected to have meant originally "coming from or belonging to the sea," the supposed stopping place of the soul before birth or after death [Barnhart]; if so, it would be from Proto-Germanic *saiwaz (see sea). Klein explains this as "from the lake," as a dwelling-place of souls in ancient northern Europe.

The meaning "disembodied spirit of a deceased person" is attested in Old English. As a synonym for "person, individual, human being" (as in every living soul) it dates from early 14c. Soul-searching (n.) "deep self-reflection, examination of one's conscience" is attested from 1871, from the phrase used as a present-participle adjective (1610s). Distinguishing soul from spirit is a matter best left to theologians.

word-forming element attached to nouns (and in modern English to verb stems) and meaning "full of, having, characterized by," also "amount or volume contained" (handful, bellyful); from Old English -full, -ful, which is full (adj.) become a suffix by being coalesced with a preceding noun, but originally a separate word. Cognate with German -voll, Old Norse -fullr, Danish -fuld. Most English -ful adjectives at one time or another had both passive ("full of x") and active ("causing x; full of occasion for x") senses.

It is rare in Old English and Middle English, where full was much more commonly attached at the head of a word (for example Old English fulbrecan "to violate," fulslean "to kill outright," fulripod "mature;" Middle English had ful-comen "attain (a state), realize (a truth)," ful-lasting "durability," ful-thriven "complete, perfect," etc.).

1946, "instinctive quality felt by Black Americans as an attribute," jazz slang, from soul (n.1), probably in the sense of "the animating or essential part." From this sense are formations such as soul brother (1957), soul sister (1967), soul food (1957 in this sense, c. 1200 as "spiritual sustenance"), etc. Soul music, originally a type of popular music typically sung by Black singers and combining elements of R&B and gospel, is so called by 1961; William James used the term in 1900, in a spiritual/romantic sense, but in reference to inner music.