1. Aberration : something that differs from the norm
(In 1974, Poland won the World Cup, but the success turned out to be an aberration, and Poland have not won a World Cup since)
(the robbery was an aberration because the town was normally safe.)
2. Acquiesce : to agree without protesting
a. (The timid, shy girl acquiesced with the man when threatened at gunpoint.)
b. (Though Mr. Pospieszny wanted to stay outside and work in his garage, when his wife told him that he had better come in to dinner, he acquiesced to her demands.)
Assent implies agreement, especially as a result of deliberation: They readily assented to our suggestion.
Agree and accede are related in the sense that assent has been reached after discussion or persuasion, but accede implies that one person or group has yielded to the other: "It was not possible to agree to a proposal so extraordinary and unexpected" William Robertson. "In an evil hour this proposal was acceded to" Mary E. Herbert.
Acquiesce suggests passive assent because of inability or unwillingness to oppose: I acquiesced in their decision despite my misgivings.
Consent implies voluntary agreement: Her parents consented to her marriage.
Concur suggests that one has independently reached the same conclusion as another: "I concurred with our incumbent in getting up a petition against the Reform Bill" George Eliot.
Subscribe indicates hearty approval: "I am contented to subscribe to the opinion of the best-qualified judge of our time" Sir Walter Scott
3. Alacrity : promptness in responce, eagerness
( accepted the invitation with alacrity)
4. Arcane: Secret known only by a few
It is also worth mentioning that arcane TENDS to be used to describe things that are mysterious because they are ancient. Languages such as Sandskrit and ancient rituals may be described as arcane.
("She knew a lot about Sanskrit grammar and other arcane matters." )
(The professor is an expert in arcane Kashubian literature.)
4.2. Cabalistic : Having secret or hidden meaning
4.3 . Occult - hidden
(hidden and difficult to see; "an occult fracture"; "occult blood in the stool")
(Planets and stars often are occulted by other celestial bodies)
4.4 Recondite - not easily understood, abstruse,concealed , hidden
5. Effrontery - brazen boldness
(I wonder—yes I wonder how he has the effrontery to look me in the face, to dare to claim acquaintance with me.)
5.1 temerity - boldness or audacity