If something is “sylvan,” it is related to forests or trees. The word ultimately is derived from the Latin “silva,” meaning forest. Its related English words are rarely used in daily discourse: “silviculture” (meaning the practice of maintaining forests) and “silvology” (meaning the study of forests).

If a group is unfamiliar with the outside world, they are often isolated in their mental habits. Such a group is called “insular” because they live as though they were on an island. The word “insular” is indeed derived from the Latin word for “island,” namely, “insula.” Related English words are “insulation” and “peninsula.” 

Do not be fooled by the option “humanist”, which really means having a philosophy or approach to learning that places the study of man, his culture, and life first. If someone is a humanist, they do not necessarily wish to aid other humans (though they might be readily inclined that way); however, someone with “humanitarian” sympathies is such a person who wishes to help in the betterment of the human condition for others.

Although many of the options are tempting here, the key phrase is “in direct proportion to the number of words . . .” If someone is “verbose,” he or she expresses something in more words than necessary. The word is clearly related to many other “word-related” words such as “verbal,” “verb,” “verbatim,” and “proverb.”

If someone is parsimonious, he or she is either frugal or even stingy. The word is derived from a Latin base meaning to be sparing and is found in the English word “parsimony.” Although this latter word often has the same economic sense as “parsimonious”, it often is used in the expression “principle of parsimony”, which indicates a class of principles used to decide the best hypothesis in a given situation by judging which has the least number of assumptions or presuppositions.

The key expression here is “having little real content.” The words were therefore empty or “vacuous,” a word with clearly related terms like “vacuum” and “vacuity.”

Since the group fears publicity, they must wish to meet in secret. Particularly given the potential negative overtones associated with their work (see “controversies”), the word “clandestinely” meets the needs of this sentence very well. To do something clandestinely means to do it secretly, particularly because it is unseemly or perhaps even illegal.

We have two clues in this sentence. First, the programmer is new to his career. Secondly, there is much to be left learned in his coming years. Do not be fooled by "youthful" or "incompetent." The latter is too strong and the former merely tempts because of its resonances with the beginning of the career. (This could be a middle aged career change, could it not?)

The correct answer, "neophyte." is derived from two Greek components. “Neo” means new (as in words like neonatal—newly born). “Phyte” derives from the Greek for plant that has a particular habitat (indicated by its prefix). Here, neophyte means one newly planted, or something more like a novice.

The best word is “venerable,” which captures the sense of respect—great but not as overstated as “awe-inspiring.” A venerable person is respectable because of age or character.

The word is derived from related Latin words with similar meanings. We find the word also used in titles of holy men by the Catholic Church, who names someone “venerable” as a stage before potentially naming the person a “saint.” 

The key is to note that the astronaut is glad to return to terrestrial (or “earth-bound”) affairs. The answer will be the contrast between these and our word. Do not be tempted by “astrological,” which deals with predicting the future through the stars (as through horoscopes). This is tempting because it has the same “astr-” prefix as is found in “astronomical,” which means dealing with the laws (from Greek nomos—reflected in "nomical") of the stars (from the Greek aster).

 Our answer, “celestial,” is equally well derived, however.  It comes from the Latin caelum (and related words such as caelestis), which means “heaven” or “sky.”  This works better (not having the occult connections of the astrologers).