single word for metta in English language

I have been struggling to find a single English word for "metta".Think I have failed. Once I read "what Buddha thought"by Walpola Rahula Thero mentioned as Universal Love which I don't agree as universe is man made theory. Also love is an attachment. so if someone mention a single word for "metta" please. So are there any single word? If there is not single word,what the reason?