1A conjunction meaning 'but' or 'however', used to mark contrast with what was just said; common in spoken Japanese.
行きたい。でも、時間がない。
I want to go. But I don't have time.
彼は親切だ。でも、時々厳しいところがある。
He's kind. However, he can be strict sometimes.
安い。でも品質はそれなりだ。
It's cheap. Still, the quality is what you'd expect.
2A particle meaning 'even' when used as '〜でも' (e.g., 'even X'). It often emphasizes an example or shows that something holds despite a condition.
子どもでもわかる説明をしてください。
Please explain it in a way even a child can understand.
一万円でも高すぎる。
Even 10,000 yen is too expensive.
学生でも参加できます。
Even students can participate.
3A particle used to express concession ('even if', 'no matter how'), as in 'even if it rains' or 'no matter how X'.
雨でも行きます。
I'll go even if it rains.
いくらでも相談に乗りますから、遠慮しないでください。
I'll give you as much advice as you need, so don't hesitate.
元気でも無理しないで休んでください。
Even if you feel fine, don't push yourself — take a rest.
4A particle used after a noun to make a casual suggestion or soften a proposal ('... or something', 'how about ...?').
映画でも見に行かない？
Shall we go see a movie or something?
コーヒーでも飲む？
Want to grab a coffee or something?
疲れたら少し休憩でもしよう。
If you're tired, let's take a break or something.
5Used in the pattern '〜でも〜でも' to list alternatives or indicate that any of the listed options are acceptable ('either A or B').
コーヒーでも紅茶でもいいです。
Either coffee or tea is fine.
肉でも魚でも何でも食べます。
I eat anything — meat or fish, whatever.
6A limited, prefix-like use before an occupation or title implying someone is only a so-called or nominal holder of that role.
自称医者でも、資格がない人には注意してください。
Be careful of people who call themselves doctors but have no qualifications.
7A colloquial, prefix-like use indicating resignation or a lack of better options (seen in forms like '〜でもしか'), i.e., settling for something for lack of anything better.
仕方がないから臨時でも手伝いに行くよ。
Since there's no other choice, I'll go help out as a temp, for lack of anything better.