The study tackles the cognitive mechanisms found in hand idioms in Egyptian dialect and some issues in rendering them into English. Hand idioms in Arabic, in general, and particularly in the Egyptian dialect refer to different conventional meanings in the conceptual domains. The study adopts Johnson and Lakoff's Conceptual Theory of Metaphor (Lakoff and Johnson, 2008). It examines 10 figurative expressions of hand idioms in Egyptian Colloquial Arabic (ECA). Most of the samples selected have similar equivalents or near-equivalents in the English language which support the universality of basic metaphors of hand idioms. Traditionally, it is argued that metaphorical idiomatic expressions have arbitrary senses. However, in cognitive linguistics, according to Lakoff, they are motivated rather than arbitrary and pronounced automatically in the conceptual system. The selected hand idioms are proposed to be derived from a set of conceptual mappings that is realised from a source and a target domain based on the Cognitive Theory of Metaphor developed by (Lakoff and Johnson 1980). The study shows that the figurative meanings of the selected data are cognitively achieved by conceptual metonymy, conventional knowledge, and conceptual metaphor respectively. It also finds that conceptual metonymy and conventional knowledge constitute the main tool in motivating and understanding the hand idioms in ECA. Additionally, the literal translation of hand idioms would not be a good option due to the culture-specific references embedded.