What is the closest word to "king"? Is it "Canute" or is it "crowned"? There are many ways to define "similar words" and "similar texts". Depending on your definition you should choose a word embedding to use. There is a new generation of word embeddings added to Gensim open source NLP package using morphological information and learning-to-rank: Facebook's FastText, VarEmbed and WordRank.
There are many ways to find similar words/docs with an open-source Natural Language processing library Gensim that I maintain. I will give an overview of modern word embeddings like Google's Word2vec, Facebook's FastText, GloVe, WordRank, VarEmbed and discuss what business tasks fit them best.
What is the most similar word to "king"? It depends on what you mean by similar. "King" can be interchanged with "Canute", but it's attribute is "crown". We will discuss how to achieve these two kinds of similarity from word embeddings.