A famous and much loved English socialist MP Tony Benn described Socialism as "A democratic, equal and fair society based on co-operation rather than competition". This is the one I always trot out (no pun intended) when I am asked this question. Professor Richard Wolfe has a great breakdown here http://topdocumentaryfilms.com/capitalism-marxism-socialism/
Typical socialist sophistry, in reality socialism promotes more competition for political advancement in order to attain privileges unavailable otherwise, while capitalism promotes more co-operation through the alignment of self interests into a common mutual benefit through free exchange. "Equal and fair society", is newspeak for an oppressive and freedomless dystopia (scores and scores of proof of this can be found in every single try that socialism has been attempted, and it has always ended in a totalitarian nightmare); "based on co-operation", newspeak for forced labor and no dreams or hope of progress possible where everyone (except for the one party power structure members) is leveled down into misery. Socialism actually just changes the type of competition, from one directed at achieving self improvement (and because of it an improvement in society in general) through fair market exchange (which has served to elevate humankind to the place it is today, creating wealth, health, and a general increase in wellbeing) to another type of competition for elevation through political advancement in a one party hellish totalitarian freakstate (a cero sum game that only creates misery, oppression, despair, and death, once again proven scores and scores of times wherever it has been tried and failed). Bastiat sums it up brilliantly:
No more, no less, and by the way my favorite Englishman is Churchill.
Keep on trotting.