War-torn describes a country, city or region that war has damaged badly — buildings in ruins, people driven from their homes, ordinary life broken. 'a war-torn nation', 'the war-torn east of the country', 'war-torn Syria'.

It is an adjective you put in front of a noun; we do not usually say 'the country is war-torn' — we say 'the war-torn country'. Almost always the noun is a place: a country, a city, a region, a border. You can stretch it to a period of time ('war-torn years') or to a group of people's lives, but a place is the normal home for it.

The word belongs to news reporting and to appeals from charities. It is emotional, not neutral — you choose it because you want the reader to feel the damage. That is also its weakness: it is used so often in headlines and fundraising letters that it can slip into cliché, and a careful writer sometimes avoids it for that reason. Notice too that it flattens things. Calling a place 'war-torn' can make it sound as though ruin is all there is, when people there are still going to school and running shops. Journalists have been criticised for this. You can use the word, but use it knowing what it does.

The present tense is 'tear', and 'torn' is its past participle — the image is of cloth ripped apart.