形容詞 impracticable:

1. not capable of being carried out or put into practice
   同義詞：infeasible, unfeasible, unworkable

1. Originally Edison used platinum alloys for the filament, in the belief that carbon was impracticable.
   愛迪生不相信碳可作燈絲用，所以一開始就用鉑合金作燈絲。
2. It's evident that the plan is impracticable.
   很明顯這計(jì)劃是不能實(shí)現(xiàn)的。
3. The plan is impracticable.
   這個(gè)計(jì)劃是不可行的。
4. It was impracticable to think that we could build the house in one week.
   以為我們用一周的時(shí)間就能把房子蓋好，這種想法是不切實(shí)際的。

im.prac.ti.ca.ble

adj.（形容詞）
Impossible to do or carry out:
不能實(shí)行的，行不通的：
例句：
Refloating the sunken ship intact proved impracticable because of its fragility.
由于沉船的易碎性使整艘沉船的重新上浮被證明是行不通的

Unfit for passage:
不適于通行的：
例句：
roads impracticable in winter.
在冬天不能通行的路

Archaic Unmanageable; intractable.
【古語】 難處理的；難對(duì)付的

【引伸】
imprac.ticabil.ity 或
imprac.ticableness
n.（名詞）
imprac.ticably
adv.（副詞）
Impracticable applies to a course of action that is impossible to carry out or put into practice;impractical, though it can be used in this way, also can be weaker in sense,suggesting that the course of action would yield an insufficient return or would have little practical value.A plan for a new baseball stadium might be rejected asimpracticable if the site was too marshy to permit safe construction; but if the objection was merely that the site was too remote for patrons to attend games easily,the plan would better be described asimpractical. See Usage Note at practicable
Impracticable 用于不可能實(shí)行或行不通的動(dòng)作過程；impractical 雖然也能這樣用， 但也有較弱意思的用法，指動(dòng)作過程能產(chǎn)生不足的回報(bào)或者幾乎沒有實(shí)際的價(jià)值。如果建筑地點(diǎn)過于濕軟而不能保證穩(wěn)固的建筑，那么修建棒球體育場的計(jì)劃就可能因其impracticable （不可行）而遭到反對(duì)； 但是如果反對(duì)的理由僅僅是場址太偏遠(yuǎn)而使得愛好者們不能輕易到場觀看比賽的話，這個(gè)計(jì)劃還是應(yīng)該被看成是impractical（不切實(shí)際的） 參見 practicable