Antonyms of adj practicable

2 senses of practicable

Sense 1
operable, practicable -- (usable for a specific purpose; "an operable plan"; "a practicable solution")

INDIRECT (VIA practical) -> impractical -- (not practical; not workable or not given to practical matters; "refloating the ship proved impractical because of the expense"; "he is intelligent but too impractical for commercial work"; "an impractical solution")

Sense 2
feasible, executable, practicable, viable, workable -- (capable of being done with means at hand and circumstances as they are)

INDIRECT (VIA possible) -> impossible -- (not capable of occurring or being accomplished or dealt with; "an impossible dream"; "an impossible situation")

Similarity of adj practicable

2 senses of practicable

Sense 1
operable, practicable -- (usable for a specific purpose; "an operable plan"; "a practicable solution")
       => practical (vs. impractical) -- (concerned with actual use or practice; "he is a very practical person"; "the idea had no practical application"; "a practical knowledge of Japanese"; "woodworking is a practical art")

Sense 2
feasible, executable, practicable, viable, workable -- (capable of being done with means at hand and circumstances as they are)
       => possible (vs. impossible) -- (capable of happening or existing; "a breakthrough may be possible next year"; "anything is possible"; "warned of possible consequences")