The answer is porous. Milady's chemical-texture-services chapter matches this question almost word for word: porous hair has a raised cuticle layer that easily absorbs chemical solutions, and needs a less alkaline solution to avoid damage.
Resistant hair is effectively the opposite: the same chapter describes it as having a tight, compact cuticle layer that resists chemical penetration, requiring a more alkaline solution instead. Coarse and dense describe strand diameter and hair-per-square-inch count, not cuticle behavior.
Milady Standard Barbering, 6th ed., Ch. 17 (Chemical Texture Services), p. 582: "Porous hair has a raised cuticle layer that easily absorbs chemical solutions. This hair type requires a less alkaline solution to help prevent damage to the hair."
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