The list of words which are published in the Barron's, "GRE Big Book" which may assist in understanding some of the phrases better are as follows:

introspection examining one's own thoughts and feelings
philanthropist one who loves mankind
antidote medicine used against a poison or a disease
strive to make great efforts, to struggle
ambidextrous able to use the left hand or the right equally well
retrospective Looking back on past
precursors a person or thing that precedes, as in a process or job.
introvert one who turns towards himself
gerontocracy government ruled by old people
ambiguous doubtful; uncertain
braggart boastful
aggravate make worse; irritate
entice attract, lure
alleviate make (pain) easier to bear
adorn add beauty; decorate
equilibrium state of being balanced
abhor to hate; to detest
connote Suggest or imply in addition to the precise, literal meaning
endeavor to make an effort, to try very hard
agile active; quick-moving
renovate restore something to better condition
curriculum course of study
malevolent malicious; evil; having or showing ill will
amalgamate mix; combine; unite societies
xenophile (zen-uh-fahyl) a person who is attracted to foreign peoples cultures
drowsiness feeling sleepy half asleep
stray wander lose one's way
disrobe undress
acumen Keen, quick, accurate insight or judgment
suffocate cause or have difficulty in breathing
sporadic happening from time to time
scent smell (especially pleasant)
sequence succession connected line of
audacious Bold
affinity close connection; relationship
animosity strong dislike
heterogeneous made up of different kinds
fragile easily injured broken or destroyed
legacy Bequest or inheritance
massacre cruel killing of a large number of people
appease make quiet or calm
submerge put under water liquid sink out of sight
adulteration making unpure; poorer in quality
combustion process of burning
premature doing or happening something before the right time
shunned avoided, kept away from
anguish severe suffering
apt well-suited; quick-witted
conceal hide keep secret
grumble to complain
indigenous native
offhand Without preparation or forethought
loll rest to sit or stand in a lazy way hang (dog's tongue)
correlate have a mutual relation
somersault rolling backward or forward (not sideways) movement
abscond to go away suddenly (to avoid arrest)
edible fit to be eaten/not poisonous
extinguish end the existence of/wipe or put out
inquest Legal or judicial inquiry, especially before a jury and especially made by a coroner into the cause of someone.s death
surcharge additional load/charge
accolade praise; approval
conjoin to join together
timid shy easily frightened
opaqueness dullness/not allowing light to pass through
disallow refuse to allow or accept as a correct
abide be faithful; to endure