From Longman Dictionary of Contemporary Englishicilyi‧ci‧ly /ˈaɪsəli/ adverb ANGRYUNFRIENDLYif you say something icily, or look at someone icily, you do it in an angry or very unfriendly way ‘I want you to leave now, ’ she said icily.
Examples from the Corpus
icily• They are all blond and call themselves Gang, without the definite article, which has an icily Germanic ring. 