Oiltight

Part of speech: adjective

Definitions

1. Manufactured to ensure no oil can infiltrate or escape
2. Built to resist the penetration of oils and keep them contained
3. Made so that oil cannot pass through or leak out

Etymology: "Oiltight" is a plain compound: "oil" joined to "tight," meaning a container or seal through which oil cannot pass. The second element carries the sense, since "tight" in the sense of impermeable or watertight has long been used of containers, joints and seals. The pairing follows the same pattern as "airtight" and "watertight," where a substance is named and the adjective states that it cannot get through. The word's value lies in its practical use rather than any dramatic shift in meaning. It describes things built to hold lubricants, fuels or other oils in or out, such as engine casings, gearboxes and sealed machinery. Its meaning has stayed close to its literal parts throughout.

Synonyms: waterproof, leak-proof, sealed, impermeable, tight

Antonyms: leaky, porous, open, insecure, vulnerable