Лёгкий: light, easy, easy-going, low-cal
With the weather in Moscow apparently permanently stuck in winter mode — minus 5 degrees Celsius in April? Blizzards? Give me a break! It's hard to work up a properly light and spring-like mood. This may be in part because of the 10-kilo down parka, 8-kilo boots and 5 kilos of woolens I'm dragging around. Why go to the gym to lift weights? I do it every time I walk out of the house.
To counteract this, these days my favorite word is лёгкий (light). Just saying it is like inhaling and exhaling a summer breeze: Breathe in on the softest л, take in a mouthful of the airy ё, let the г dissolve into a breathy х, tap out a quick к, and then breathe out with a long, soft ий. There isn't a lighter word in the world.
And лёгкий is a very handy little adjective. It refers to anything that doesn't weigh much, like лёгкий чемодан (a light suitcase). Or it can mean something that doesn't provide much protection against the elements, like лёгкая куртка (light jacket) or лёгкое одеяло (thin blanket). It can also refer to something that might be very heavy but looks fragile or airy, like a fortress spire: Стройная и фантастически лёгкая башня увенчана огромным 5-метровым флюгером (The slender and fantastically delicate tower is topped with a huge, five-meter weathercock).
When лёгкий modifies forms of transportation, creatures and movement, it means quick, maneuverable and elegant. Это лёгкий, живой, жизнерадостный танец (It's a quick, lively, joyful dance). Лёгкая музыка, however, is what Americans call "easy listening."
Лёгкий can also mean something insubstantial: Сегодня идёт лёгкий снежок (It's lightly snowing today). У меня лёгкая досада (I'm mildly annoyed.) Or barely noticeable: Еле услышал лёгкий вздох (I barely felt the gentle sigh). Or exerts a mild effect: Она курит лёгкие сигареты и пьёт только лёгкое белое вино (She smokes light cigarettes and only drinks light, white wine).
Лёгкий also refers to anything that is easy to do, from лёгкая задача (an easy task) to лёгкое чтиво (light reading). Лёгкий ужин is a light dinner, and лёгкий on food labels means that it is low in calories, like лёгкий майонез (lite mayonnaise).
When applied to some kind of achievement, лёгкий means that it was done without difficulty. But Russians are a bit skeptical about the value of лёгкие деньги (easy money), лёгкая победа (easy victory), лёгкая жизнь (easy life), and лёгкий успех (easy success).
People can be лёгкие in terms of weight: Подними её! Она лёгкая (Pick her up — she's not heavy). But лёгкий человек is someone who is easy-going. Мы с ним хорошо сработались. Он же очень лёгкий человек. (We worked well together. He's such a laid-back guy.)
But when referring to morals, лёгкий implies devil-may-care or worse. Женщина лёгкого поведения is a woman who is "easy" — and often takes money for her efforts.
And speaking of the devil, лёгок на помине (literally, "light on the tongue") means just that. There are several explanations of the Russian phrase. In one, лёгкий was a term used to describe the devil, presumably because he is nimble and quick. Now the phrase is used when someone appears just after you've mentioned him.
And then there's лёгок на подъём (ready to go at the drop of a hat), something I am definitely not these days (see above).