1: To make valid or binding usually by a formal procedure (such as ratification)
2: To give effective or authoritative approval or consent to
The Latin sancire, meaning "to make holy," is an ancestor the word.
1: The troops moving at the head of an army
2: The forefront of an action or movement
Vanguard and avant-garde both derive from the Anglo-French word avantgarde, itself from avant, meaning "before," and garde, meaning "guard." In medieval times, avantgarde referred to the troops that marched at the head of the army. English speakers retained that meaning when they adopted vanguard in the 15th century.
1: Full of, actuated by, or exhibiting capricious or eccentric and often sudden ideas or turns of the mind: relating to whims
2 a: Resulting from or characterized by whim or caprice; especially: lightly fanciful
Whimsical and the related nouns whim and whimsy all ultimately derive from whim-wham, a noun from the early 16th century that originally referred to an ornamental object or trinket. Later whim-wham, with its fun sound, came to refer to a fantastic notion or odd fancy. The word's origin isn't clear, but it's worth noting that the similar-sounding flimflam had, in its earliest use, a similar meaning referring to an odd or nonsensical idea or tale