Synonyms of the word

impermeable

• adj. impossible to permeate.
• adj. not allowing passage, especially of liquids; waterproof.

imperviable

• adj. impervious.

impervious

• adj. Unaffected or unable to be affected by.
• adj. Preventive of any penetration; impenetrable, impermeable, particularly of water.
• adj. Immune to damage or effect.

retentive

• adj. Having power to retain.
• adj. (slang, apocope) anal-retentive.
• n. (obsolete) That which retains or confines; a restraint.

tight

• adj. Firmly held together; compact; not loose or open.
• adj. (of a space, design or arrangement) Narrow, such that it is difficult for something or someone to pass…
• adj. Well-rehearsed and accurate in execution.
• adj. (slang) Intoxicated; drunk or acting like being drunk.
• adj. (slang) Extraordinarily great or special.
• adj. (slang, British (regional)) Mean; unfair; unkind.
• adj. (obsolete) Not ragged; whole; neat; tidy.
• adj. (obsolete) Handy; adroit; brisk.
• adj. (poker) Of a player, who plays very few hands.
• adj. (poker) Using a strategy which involves playing very few hands.
• adv. Firmly, so as not to come loose easily.
• adv. Soundly.
• v. (obsolete) To tighten.

water-repellent

• adj. that slows the penetration of water (but is not waterproof).
• n. Alternative spelling of water repellent.

water-resistant

• adj. that slows the penetration of water (but is not waterproof).