Subjects were presented with rare words, and required to define them. Feeling-of-knowing judgements were made with respect to meaning of words that could not be defined accurately. It was found that subjects’ feeling-of-knowing judgements accurately predicted their performance on semantic-differential and related-word tasks designed to measure connotative and denotative aspects of word meaning, respectively. In addition, number of semantically related words recognized was consistently related to both feeling-of-knowing judgements and to semantic-differential performance. It was concluded that feeling-of-knowing judgements and their predictive accuracy were result of knowledge of semantic attributes or features.