To give you a bit more context as you wanted as much as possible:

perilous - dangerous, but more than that possibly leading to tragedy or peril (death). The early sttlers coming to the new world faced a perilous journey because many of them perished (died) trying to get to America.

daunting - a task that is daunting may seem impossible. It is extremely difficult, to say the least. It may have seemed like a daunting task to undertake a journey to a new world, but in the end the settlers who came to America were successful.

formidable - formidable is a lot like daunting. It is extremely difficult.

demeaner - this word is actually spelled demeanor and it refers to the way that you carry yourself. If yoiu want to get a job, than you should present yourself at the interview with a professional demeanor.

alfalfa - alfalfa is a type of hay. It is commonly fed to horses, but it is high in both protein and energy. The racehorses were given alfalfa nightly to add calories and energy to their diets.

corrupt - this word means lacking in morals, dishonest, and is generally applied to large groups such as governments or corporations. The government of Mexico, for example, is viewed as corrupt as the police often take kickbacks to to look the other way when the drug dealers do business.

regime - this is a type of ruling body or set of political conditions. Hitler's regime, for example, was one that led to the persecution of all non-Aryans in Germany.

The previous post did a good job of addressing the words' meanings.  You went with "the more the better," which is where I am going.  I think that the idea of perilous and daunting are fairly similar in that they both refer to a sense of challenge evident in a particular task.  "Formidable" is also similar in that it helps to articulate a condition that should be heeded and not be underestimated.  There has to be a "demeanor" with those particular concepts (formidable, perilous, daunting) that does not show a great level of fear in the face of such elements of challenge.  Sometimes, this demeanor is needed to challenge political regimes that are corrupt.

perilous means pretty much the same thing as dangerous, only fancier.

daunting means sort of scary -- like the idea of speaking in front of 500 people might be daunting.

formidable means strong or impressive.

demeanor is your attitude, the way you seem -- like you might have a pleasant demeanor.

alfalfa is a kind of crop that is grown for hay.

corrupt means to be in some way rotten.  We usually use it today in a figurative sense.  Someone is corrupt if they take bribes.

regime is a government -- usually spoken of in a bad way.  We talk about Saddam Hussein's regime, but we don't talk about Obama's regime unless we don't like him.