Longman Dictionary: Words of the day; random words

headstrong - упрямый, своевольный;
very determined to do what you want, even when other people advise you not to do it
// Leo's parents soon found that they were completely unable to control their headstrong son.
// How did one stop a person like Harriet, headstrong, independent, beholden to no one?

humane - гуманный, человечный, гуманитарный
treating people or animals in a way that is not cruel and causes them as little suffering as possible
// a better, more humane world

dependable - надежный, заслуживающий доверия
// our most dependable ally
// a dependable source of income

apprehensive - опасающийся, полный страха, полный предчувствий
                            worried or nervous about something that you are going to do, or about the future
// We’d been a little apprehensive about their visit.
// I was apprehensive that something would go wrong.
// Some had apprehensive looks on their faces.
// Twenty minutes in his company had left Merrill feeling stretched and apprehensive.
// I must admit that before my baby was born I was very apprehensive about motherhood.
// No one need be apprehensive about their personal safety; everything is under control.

apprehensive that
// They were deeply involved in the welfare of their families - apprehensive that something might go wrong.

—apprehensively adverb  

// ‘What’s wrong?’ I asked apprehensively.
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accidentally - случайно; in a way that was not planned or intended deliberately
// She accidentally dropped the vase on her foot
// I met the man purely by accident, and we began a conversation.

praying mantis - Богомол
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unintentional - непреднамеренный; неумышленный
not done deliberately
// I know she upset you, but I’m sure it was unintentional.
// Some of these things are done to us deliberately while others are the unintentional actions of others or unavoidable events.
// Gingrich said his violations were unintentional and that he regretted them.
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deteriorate - ухудшаться; to become worse
// Ethel’s health has deteriorated.
// America’s deteriorating economy
Register:
In everyday English, people usually say get worse rather than deteriorate:
// Her health got worse.
// The situation is getting worse.

downside - the negative aspect of something otherwise regarded as good or desirable
// he says being a rock star is a fun line of work when you're young, but admits fame can have its downsides
// The downside is that it can be obtained only through brokers and financial advisers.

the downside - the negative part or disadvantage of something; Обратная сторона;
// The downside of the book is that it is written in a rather boring style
// The downside of this, however, is that they tend not to pay out as much as higher-risk investments

upside - (especially American English) the positive part of a situation that is generally bad
// Of course, there is an upside to every quandary.
// Where, really, is the upside here?
// So what's the upside then?

quandary - (syn: dilemma)  a difficult situation or problem, especially one in which you cannot decide what to do
затруднительное положение,  затруднение
// Kate is in a quandary
// This put Mr Babbitt in a quandary
// Perhaps if I could ask you a few questions, it might help me in my quandary
// But they were in a quandary about how to blend their vastly different tastes

quandary - a difficult situation; a practical dilemma.
// "a legal quandary"