Most of the adjs. in -ful are formed from nouns denoting feelings, attitudes, mental or moral states, or the like. (a) Some are inherited from OE, e.g. care-ful sorrowful, troublesome; eie(s)-ful frightening; bale-ful wretched, malignant; shame-ful modest, disgraceful; sin-ful sinful, wicked; thank-ful grateful, pleasing. (b) Many are formed in ME (from native and OF nouns), e.g. dred-ful timid, intimidating, terrifying; reu-ful compassionate, pitiable; worship-ful worthy, respected; blame-ful censorious, blameworthy; feith-ful full of faith, loyal; grace-ful full of divine grace; pes-ful amicable, peaceful. The meaning of the suffix is 'full of (a feeling), characterized by (an attitude)' or 'arousing, inducing (a feeling, reaction, etc.).' Some of these adjs. were coined to render L adjs. in -ōsus, -ibilis, -ālis and OF adjs. in -able; hence, -ful is in part synonymous with the borrowed suffixes -ǒus, -āl, -āble and with the native suffix -lī(ch. This more abstract meaning appears in such late formations as lau-ful according to custom or law, legal; maister-ful master-like, imperious, high-handed; man-ful manly, brave.

A few adjs. in -ful are formed from adjs. & verbs, mostly to render L adjs. in -ōsus: derk-ful [OE deorc-ful] dark, transl. L tenebr-osus; irke-ful painful; late-ful late; treu-ful true; forȝet-ful forgetful, transl. L oblivi-osus; heri-ful praiseworthy, transl. L glori-osus.