The suffix -ful usually means characterized by or in full measure as in hateful and spoonful. But an animal's pitiful cry is not full of, or characterized by, pity, and the fearful symmetry of Blake's tyger is not full of fear. These meanings run counter to what one might naively think. How did this come about? I understand that the suffixes -ful and -ous are part of the battle between words that come through French and those that don't. Sometimes the meanings of prefixes and suffixes change dramatically at the hands of the French. Para- usually means beside, but in words through the French, like parachute, paraph and parasol, it means against. Does this have any bearing on my question? I see the meanings of piteous and pitiful are frightfully close.
The Online Etymology Dictionary notes
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.
Consider the following: an act of gang violence can be disgraceful (effecting disgrace) or a gang can be disgraceful (marked by disgrace); a joyful person feels joy, while a joyful occasion brings joy; a regretful decision may be one that causes regret but a regretful person demonstrates regret.
But in other cases, one or the other meaning never developed, or has died out. For example, the oldest meaning of pitiful in the OED is
(from ca. 1350) 1. Full of or characterized by pity; compassionate, merciful, tender. Cf. pitiable adj. 1.
But it is Now rare., and later senses of pitiful as something deserving of pity and thence contemptible have become the dominant meanings.
It appears to be from the original Old English meaning of "ful": characterized by:
- 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.