Заморить червячка: to have a bite to eat
I have a great fondness, tempered with exasperation, for Russian verbs with a half dozen different, completely contradictory meanings.
Take морить and its perfective mates заморить and уморить. They can mean to kill, starve, poison, wear out, bore to tears, give someone a belly laugh or stain — not to mention to take an edge off your hunger.
By and large, this isn't a cheery word. It has the root мор- which produces words connected with death and dying, such as умереть (to die). Морить can mean to kill with poison. Каждый год морят тараканов в нашем доме (Every year they fumigate the house to get rid of cockroaches). Sometimes the extermination can be figurative: Заморив в себе писателя, я стал простым лектором в университете (I killed off the writer in me and became a simple university lecturer).
But морить can bring death in other ways, too: by wearing people down, exhausting or starving them. Они хотят нас голодом заморить (They want to starve us to death). Голодом заморить should remind you of the noun голодомор (extermination by starvation) that is used most commonly to describe the mass starvation in Ukraine under Stalin.
Thirst, too much work, too much sun and not enough sleep can also wear a person down. Нас морила жажда (We were dying of thirst). На конференции после обеда скучные доклады почти уморили меня (At the conference, the boring presentations after lunch just about put me to sleep). Oddly to my ear, when you want to say that you are exhausted and sleepy, you say сон морит (I'm dying to go to sleep, literally "sleep is killing me").
There are two adjectives derived from the perfective verbs, заморённый (emaciated, exhausted) and уморённый (exhausted, worn out, beat). Отдыхающие, уморённые солнцем, купаньем и обедом, лежали на надувных матрасах и спали (The vacationers, exhausted by the sun, swimming and lunch, lay on air mattresses and slept). У неё был очень страшный, заморённый и измученный вид (She looked just awful — emaciated and totally worn out).
On a slightly lighter note, for DIY-ers, морить means to stain wood and has produced the noun морилка (stain). Я не знаю чем заморить шкатулку — чаем или морилкой (I can't decide what to stain the box with — tea or wood stain).
But there is a brighter side to this dark verb. Морить/уморить can mean to make someone laugh. Think of doubling over with laughter and protesting, "Stop! You're killing me!" Она хохотала, раскачиваясь. — Ну, уморил меня! (She shook with laughter. "Oh, you gave me a good laugh!") This has produced the adverb уморительно (hilariously): Клоун был уморительно смешным (The clown was hilariously funny). And the noun умора (something hilariously funny). Ты видел перевод меню! Ну, умора! (Did you see the translation of the menu? What a riot!)
And then there's the odd little idiom заморить червячка (literally, "to kill the worm"). It seems to be a calque from the French tuer le ver (to kill the worm) and referred to drinking a shot of alcohol in the morning to kill off intestinal worms. The yuck factor seems to have disappeared from the Russian perception of the phrase, which now means to have a bite to eat. Of course, the concept is relative. Чтобы заморить червячка, она дала мне яблоко (To tide me over, she gave me an apple).