〜も同然だ
Formation
Meaning
Used to express that something is in a state or condition that is virtually identical to something else, even if it is technically different.
Note
Expresses that although something is not literally the same as another state, for all practical purposes it can be treated as such. It implies a high degree of certainty or completion. It commonly connects to nouns (sometimes dropping the 'mo') or to verbs in their ta-form (completed) or nai-form (negative). The synonym '〜とど同然だ' can also be used.
Examples
この試合に勝てば、優勝したも同然だ。
If we win this match, we've practically won the championship.
これだけ準備すれば、終わったも同然ですね。
With this much preparation, it's basically finished.
親に黙って学校を休むなんて、退学したも同然の行為だ。
Skipping school without telling your parents is practically the same as dropping out.
一度も使っていないのだから、新品同然だ。
Since it's never been used, it's as good as new.
彼は私の兄も同然の存在です。
He is like an older brother to me.
あの二人は結婚していないけれど、夫婦も同然の暮らしをしている。
Those two aren't married, but they live together as if they were a married couple.