Both the Oxford English Dictionary and the Collins Dictionary give Selbstüberwindung as willpower. I refer to both in my original post. If you follow the link, you can see that the Collins dictionary gives another option that depends on context:
'Selbstüberwindung (f) willpower
das war echte Selbstüberwindung that shows real willpower
selbst bei der größten Selbstüberwindung könnte ich das nicht tun I simply couldn't bring or force myself to do it'
How can one prove that 'self-conquest' is not 'Selbstüberwindung'? When something is not there, how can one give concrete evidence of its non-existance? Certainly, I can find it in no English dictionary. It comes across as 'idiotic' because it seems to be an overliteral translation, taking in the case of 'Überwinding' a word with a similar, but not exaclty the same, meaning.
Some bright spark is going to google the word 'self-conquest' to prove me wrong. If you do so, you'll only find it in philosophical and religious quotations; and if it is a good translation of the original ancient greek or whatever, I truly cannot say. I strongly suspect that a few poor translations of certain quotations (esp. from Teresa of Avila and Plato) are responsbile for its presence in the internet. Moreover, in some cases its use is clearly metaphorical or rhetorical:
'Self-conquest is far better than the conquest of others. Not even a god, an angel, Mara or Brahma can turn into defeat the victory of such a person who is self-subdued and ever restrained in conduct.'
http://www.buddhapadipa.org/pages/dailydhamma...In this case, the word seems to have been invented to dovetail with the word 'conquest'. Thus even if people have used the word 'self-conquest', its use is clearly very limited. To take this as evidence the quality of the translation self-control=Selbstüberwindung is dangerous, especially as there is no evidence that these are good translations of the original quotations, or that the equivalent in German would be 'Selbstüberwindung'.
I realise my tone in both this and the first post was aggressive, but as a language teacher I have found that a considerable percentage of students' lexical mistakes come from bad translations they have picked up from leo.de. I am beginning to truly believe that this website does more to harm language learning than it does to promote it.