Kế hoạch này rất tệ.

Vietnamese often does not use a verb like to be when linking a noun to an adjective.

So:

• Kế hoạch này rất tệ = This plan is very bad
• literally: plan this very bad

This is normal Vietnamese sentence structure. With adjectives such as tệ (bad), đẹp (beautiful), hay (interesting/good), or khó (difficult), you usually do not add a word for is.

Này means this.

In Vietnamese, demonstratives like this and that usually come after the noun, not before it.

So:

• kế hoạch này = this plan
• literally: plan this

This is a very common pattern:

• người này = this person
• cuốn sách này = this book
• ý tưởng này = this idea

For English speakers, this feels reversed at first, but it is standard Vietnamese word order.

Rất means very.

It goes before the adjective it modifies:

• rất tệ = very bad

This is the normal order in Vietnamese:

• rất tốt = very good
• rất đẹp = very beautiful
• rất khó = very difficult

So the structure here is:

• kế hoạch này = this plan
• rất tệ = very bad

Together: This plan is very bad.

Yes, tệ is a common word for bad, especially for quality, performance, or situation.

In this sentence, rất tệ sounds fairly strong. It means the plan is not just imperfect, but seriously poor.

Some related words:

• tệ = bad, poor
• không tốt = not good (softer)
• dở = bad/poor, often for skill, quality, or performance
• tồi = bad, lousy, rather strong

So Kế hoạch này rất tệ is a direct and negative judgment. It is natural, but not gentle.

Kế hoạch is a two-syllable expression:

• kế
• hoạch

A rough guide for English speakers:

• kế sounds somewhat like kay, but shorter, and with a rising tone
• hoạch is harder; the vowel and final consonant are not exactly English sounds. The ch here is not like English church. It ends abruptly.

Important points:

• Vietnamese is tonal, so the marks matter
• kế has a tone mark
• hoạch also has tone and vowel marks

The best way to learn it is by listening to native audio and repeating, because the tones and final sounds are difficult to master from spelling alone.

It is one noun phrase meaning plan, but it is written as two separate syllables because standard Vietnamese orthography usually separates syllables with spaces.

So:

• kế hoạch = plan

Even though English writes many words as one unit, Vietnamese often writes each syllable separately. That does not mean it is two separate words in the way an English learner might think.

Many common Vietnamese words look like this:

• công việc = job, work
• bệnh viện = hospital
• điện thoại = telephone

So kế hoạch functions as one lexical item meaning plan.

The sentence follows a very common Vietnamese pattern:

Noun + demonstrative + degree word + adjective

Here:

• Kế hoạch = plan
• này = this
• rất = very
• tệ = bad

So:

• Kế hoạch này rất tệ.
• literally: Plan this very bad.

A more general pattern is:

• [thing] + này/kia/đó + [quality]

For example:

• Bộ phim này rất hay. = This movie is very good/interesting.
• Cuốn sách đó khá khó. = That book is quite difficult.

Yes. That would simply mean:

• Kế hoạch này tệ. = This plan is bad.

Adding rất makes it stronger:

• tệ = bad
• rất tệ = very bad

So both are correct, but they differ in intensity.

Yes. Vietnamese has several common options.

Stronger:

• Kế hoạch này quá tệ. = This plan is too bad / really terrible.
• Kế hoạch này tệ lắm. = This plan is very bad.
• Kế hoạch này cực kỳ tệ. = This plan is extremely bad.

Softer:

• Kế hoạch này không tốt lắm. = This plan is not very good.
• Kế hoạch này chưa ổn. = This plan is not okay yet / isn’t quite right.
• Kế hoạch này có vẻ không ổn. = This plan seems not okay.

So if you want to sound less harsh, không tốt lắm or chưa ổn is often safer than rất tệ.

It is not grammatically rude, but it is blunt.

You are making a direct negative judgment: This plan is very bad. That can sound harsh depending on the situation.

If you are speaking to:

• a boss,
• a client,
• a teacher,
• or someone whose idea you are criticizing,

you may want something softer, such as:

• Kế hoạch này chưa ổn. = This plan isn’t quite right yet.
• Kế hoạch này không khả thi lắm. = This plan is not very feasible.
• Tôi nghĩ kế hoạch này cần chỉnh sửa thêm. = I think this plan needs more revision.

So the original sentence is natural, but it is direct.

Yes.

Common demonstratives include:

• này = this
• đó = that
• kia = that over there / that one yonder

So you can say:

• Kế hoạch này rất tệ. = This plan is very bad.
• Kế hoạch đó rất tệ. = That plan is very bad.
• Kế hoạch kia rất tệ. = That plan over there is very bad.

The exact nuance depends on context and dialect, but the important grammar point is that these words usually come after the noun.

Usually, no.

In Vietnamese, classifiers are common with many countable nouns, especially when using numbers or certain determiners. But abstract nouns like kế hoạch often appear without a classifier.

So:

• kế hoạch này = this plan

is completely normal.

You might sometimes hear expressions like một kế hoạch = a plan, also without a classifier. That is very common for abstract nouns.

So for this sentence, there is no missing classifier; the phrase is already natural and correct.