pithy adj.

Old English piþa "central cylinder of the stems of plants," also, figuratively, "essential part, quintessence, condensed substance," from West Germanic *pithan- (source also of Middle Dutch pitte, Dutch pit, East Frisian pit), a Low German root of uncertain origin. Figurative sense of "energy, concentrated force, closeness and vigor of thought and style" is by 1520s. The pith helmet (1889, earlier pith hat, 1884) was so called because it is made from the dried pith of the Bengal spongewood.

adjective suffix, "full of or characterized by," from Old English -ig, from Proto-Germanic *-iga- (source also of Dutch, Danish, German -ig, Gothic -egs), from PIE -(i)ko-, adjectival suffix, cognate with elements in Greek -ikos, Latin -icus (see -ic). Originally added to nouns in Old English; used from 13c. with verbs, and by 15c. even with other adjectives (for example crispy). Adjectives such as hugy, vasty are artificial words that exist for the sake of poetical metrics.