Estaba borracho anoche.

Spanish often drops the subject pronoun when it is already clear from context.

Estaba can mean:

• I was
• he was
• she was
• you were (formal usted)

So by itself, Estaba borracho anoche could mean:

• I was drunk last night
• He was drunk last night
• She was drunk last night if the adjective changes to borracha
• You were drunk last night in the formal sense, again with agreement if needed

Spanish speakers usually do not say yo, él, ella, or usted unless they want to:

• emphasize the subject
• contrast it with someone else
• avoid confusion

For example:

• Yo estaba borracho anoche, no él. = I was drunk last night, not him.

Spanish uses estar for states or conditions, and being drunk is treated as a temporary state.

So:

• estar borracho = to be drunk

Using ser here would sound wrong in normal Spanish, because ser is generally for:

• identity
• origin
• permanent or defining characteristics
• time
• professions, etc.

Compare:

• Está borracho. = He is drunk.
• Es médico. = He is a doctor.

So in this sentence, estar is the correct verb because drunkenness is a temporary condition, not an identity.

This is a very common question because both can translate as was.

• estaba = imperfect
• estuve = preterite

With Estaba borracho anoche, the imperfect presents the state as a situation in progress or background information in the past.

It can sound like:

• I was drunk last night
• He was drunk last night with the focus on the condition itself, not on its beginning or end.

By contrast:

• Estuve borracho anoche also exists, and often sounds more like a completed past state within that time period.

Very roughly:

• estaba = focuses on the state as ongoing / descriptive
• estuve = focuses on the state as a whole event or completed period

In real life, both may be possible depending on context, but learners should know that estaba is very natural when describing how someone was.

On its own, estaba does not tell you exactly who the subject is. It can refer to several subjects, depending on context.

Possible meanings include:

• I was drunk last night
• He was drunk last night
• You were drunk last night (formal usted)

The adjective helps with gender:

• borracho suggests a masculine subject
• borracha would suggest a feminine subject

So:

• Estaba borracho anoche. = could be I/he/usted was drunk last night if the person is male
• Estaba borracha anoche. = could be I/she/usted was drunk last night if the person is female

If you want to make the subject clear, you can add it:

• Yo estaba borracho anoche.
• Él estaba borracho anoche.
• Ella estaba borracha anoche.
• Usted estaba borracho / borracha anoche.

Borracho is an adjective, so it must agree with the person it describes.

Forms:

• borracho = masculine singular
• borracha = feminine singular
• borrachos = masculine plural or mixed plural
• borrachas = feminine plural

Examples:

• Estaba borracho anoche. = said by/about one male
• Estaba borracha anoche. = said by/about one female
• Estaban borrachos anoche. = they were drunk last night
• Estábamos borrachas anoche. = we were drunk last night, all female speakers

This agreement is one of the main clues to who the subject might be when the pronoun is omitted.

Anoche means last night.

It is a single word in Spanish, unlike English, which uses two words.

In this sentence:

• Estaba borracho anoche. = I/he was drunk last night

Its position is fairly flexible. You could also say:

• Anoche estaba borracho.

Both are natural. The difference is mostly about emphasis:

• Estaba borracho anoche puts the time at the end
• Anoche estaba borracho highlights last night first

In Spain, borracho is very common and natural, but it is also fairly direct.

It usually means:

• drunk
• sometimes very drunk, depending on tone and context

It is not a taboo word, but it can sound blunt.

Some related options:

• bebido = has been drinking / tipsy-ish in some contexts, often softer
• ebrio = drunk, but more formal or literary
• pedo appears in some colloquial expressions, but that is more slangy and depends on region and context

For most everyday situations, borracho is the standard word learners should know.

You would change the adjective, not the verb:

• Estaba borracha anoche.

The verb estaba stays the same, because it does not change for gender. Only the adjective changes:

• male speaker / male person: borracho
• female speaker / female person: borracha

So:

• a man saying I was drunk last night: Estaba borracho anoche
• a woman saying I was drunk last night: Estaba borracha anoche

A simple pronunciation guide is:

ehs-TA-ba boh-RRA-cho ah-NO-che

A few key points for Spain:

• estaba: stress on ta
• borracho: the rr is a rolled or trilled r
• ch is like English ch in church
• anoche: stress on no

In much of Spain, the b/v sound in borracho is a soft b sound, not like a strong English b every time.

A more Spanish-style approximation:

• es-TA-ba bo-RRA-cho a-NO-che

Yes, Estaba borracho anoche is completely natural everyday Spanish.

A Spanish speaker would understand it immediately. It is a normal way to describe someone’s condition the previous night.

Depending on context, native speakers might also say:

• Anoche estaba borracho.
• Estuve borracho anoche.

But the original sentence is absolutely normal and idiomatic.

Yes. Without context, it is ambiguous.

Because Spanish often omits the subject pronoun, Estaba borracho anoche could mean:

• I was drunk last night
• He was drunk last night
• You were drunk last night if speaking formally to a man

Context normally makes it clear:

• what was being discussed before
• who the speaker is talking about
• whether the speaker is talking about themselves or someone else

If you want to remove the ambiguity, add the subject:

• Yo estaba borracho anoche.
• Él estaba borracho anoche.
• Usted estaba borracho anoche.