deceitful (adj.)

c. 1300, "trickery, treachery, lying," from Old French deceite, fem. past participle of deceveir, decevoir, from Latin decipere "to ensnare, take in, beguile, cheat," from de "from" or pejorative (see de-) + capere "to take," from PIE root *kap- "to grasp."

From mid-14c. as "act or practice of deceiving," also "false appearance, illusion." From late 14c. as "quality of being false or misleading."

Deceit is a shorter and more energetic word for deceitfulness, indicating the quality; it is also, but more rarely, used to express the act or manner of deceiving. The reverse is true of deception, which is properly the act or course by which one deceives, and not properly the quality; it may express the state of being deceived. Fraud is an act or series of acts of deceit by which one attempts to benefit himself at the expense of others. It is generally a breaking of the law; the others are not. [Century Dictionary]

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.).