Nocivo means harmful, injurious, damaging. Here is an example sentence: El tabaco es nocivo por el alquitrán y la nicotina que contiene. (Tobacco is harmful due to the tar and nicotine that it contains.)
You can take the test to see if you can spell the 15 Spanish words that many people often misspell at La Ortografía Infinita.
to complicate matters, to make things difficult, to split hairs, to nitpick
Of course, literally, this phrase means to look for three feet on a cat. But what one really intends to express with this idiomatic expression (modismo) is: to complicate things or to look for trouble. It is easy to locate a four legged cat, but three legged cats are more difficult to come by! To use some English idioms as a definition for this expression you could say: make a mountain out of a molehill or to go over something with a fine tooth comb.
No hay que buscarle tres pies al gato. (No need to go looking for trouble.)
Estoyhasta las narices de tu desorden. (I am fed up with your mess.)
Practica Español has a list of 78 Spanish expressions using body parts. In addition to hasta las narices, you can find ir con pies de plomo (to tread carefully), traer de cabeza (to drive someone mad), no tener pelos en la lengua (not to mince words), sacar los ojos (to quarrel), tener el agua al cuello (to be up to one’s neck in it), and venir como anillo al dedo (to be just right).
Some informal commands in Spanish are irregular in the affirmative. These occur with the pronoun tú. These commands are: poner – pon, decir – di, hacer – haz, salir – sal, tener – ten, venir – ven, ser – sé, ir – ve. Below are some example sentences using each of these eight verbs.