Corrupt and venal apply to a person or act, especially in public office, whose motives are mercenary and self-interested, without regard for honor, right, or justice. Corrupt, the much more familiar term, is used of institutions (corrupt government, corrupt system) as well as individuals (corrupt politicians), whose morals have been eroded by temptations of power, especially bribery. Venal, which originally meant “for sale,” tends to be used of individuals and their actions (venal politician, venal motive). It often implies a more repulsive, personal quality, one that is shamelessly open to bribery, willing to sell patronage, and thoroughly debased before they entered office.
You’ll never trip over these two words again: awkward and gauche refer to a person or behavior that causes social discomfort or embarrassment by violating expected manners. For a while there, it was popular to say “Awkward!” in an embarrassing situation, because awkward often characterizes the effect of an ill-timed or graceless remark or action on all those involved: put me in an awkward position; an awkward silence descended on the meeting. Of course the offending behavior can also be described as awkward: an awkward question. Something gauche is a slightly more serious social misstep, reflecting more poorly on the offender because it stems from a lack of awareness of or sensitivity to what is appropriate or tasteful–especially within a particular social class. In terms of class, it might be gauche to clap between the movements of a sonata, put ice cubes in your wine, or ask someone how much money they make. It could also be considered gauche to complain about first-world problems when news of a human catastrophe is on everyone’s minds.
Save implies rescuing a person or thing that is in immediate danger (save a drowning man) or preventing them from imminent or further harm (save the whales, saved the old building from being demolished, save face). Salvage implies retrieval, extrication, or rescue of something valuable in the aftermath or face of a destructive event. After a building is torn down, builders might try to salvage materials, such as unique mouldings. After involvement in a scandal, you might attempt to salvage your reputation–and your marriage! And before there was business in salvaging auto parts, there was the original context of the word–the salvaging of a shipwreck or the valuable parts of it.