A simple, friendly cartoon character sitting on a low wooden stool, wearing a large, shiny gold crown. The crown symbolizes having achieved a specific status.

serlo

SEHR-loh

VerbB1compound infinitive phrase er

to be it?referring to a status or condition,to be so?confirming a quality

Also:to be one?referring to a profession or identity

Quick Reference

infinitiveser

gerundsiéndolo

past Participlesido (when used in compound tenses, 'lo' is separate)

📝 In Action

¿Es difícil ser médico? No sé, pero debe **serlo**.

Is it difficult to be a doctor? I don't know, but it must **be so**.

Ella dice que es una persona paciente, pero dudo que pueda **serlo** siempre.

She says she is a patient person, but I doubt she can **be that way** always.

Para triunfar, tienes que estar convencido de que puedes **serlo**.

To succeed, you have to be convinced that you can **do it** (be successful).

Word Connections

Synonyms

estarlo (to be it (for temporary states))

Common Collocations

poder serlo – to be able to be it
querer serlo – to want to be it

💡 Grammar Points

What 'lo' Replaces

The 'lo' attached to 'ser' is a neuter pronoun that replaces an entire concept, characteristic, or status mentioned previously. It acts like 'that' or 'so' in English.

Attachment Rule

In Spanish, pronouns like 'lo' always attach directly to the end of infinitives ('serlo') and gerunds ('siéndolo'), forming a single word.

❌ Common Pitfalls

Separating the Pronoun

Mistake: "Quiero lo ser."

Correction: Quiero serlo. The pronoun must attach to the infinitive when there is no conjugated verb before it, or when the infinitive is the main verb of the phrase.

⭐ Usage Tips

Context is Key

Always look at the sentence before 'serlo' to understand what characteristic 'lo' is referring to. Example: '¿Eres feliz?' 'Sí, quiero serlo.' ('lo' refers to 'feliz').

🔄 Conjugations

indicative

present

él/ella/usted—

yo—

tú—

ellos/ellas/ustedes—

nosotros—

vosotros—

imperfect

él/ella/usted—

yo—

tú—

ellos/ellas/ustedes—

nosotros—

vosotros—

preterite

él/ella/usted—

yo—

tú—

ellos/ellas/ustedes—

nosotros—

vosotros—

subjunctive

present

él/ella/usted—

yo—

tú—

ellos/ellas/ustedes—

nosotros—

vosotros—

imperfect

él/ella/usted—

yo—

tú—

ellos/ellas/ustedes—

nosotros—

vosotros—

View All Tenses & Moods →

✏️ Quick Practice

💡 Quick Quiz: serlo

Question 1 of 2

In the sentence 'Ella es muy inteligente y quiere seguir siéndolo,' what does 'siéndolo' mean?

📚 More Resources

Word Family

ser(to be) - verb

lo(it / him) - pronoun

Frequently Asked Questions

Is 'serlo' the only way to say 'to be it'?

Yes, when 'it' refers to an abstract idea, condition, or characteristic previously mentioned, 'serlo' is the standard and most natural way to express the infinitive form. If 'it' were a direct object noun (e.g., 'the book'), you would use 'leerlo' (to read it).

Why don't I see conjugations for 'serlo'?

'Serlo' is the base form (infinitive) of the verb 'ser' with the pronoun attached. You only conjugate the verb 'ser' itself, and then you place 'lo' before the conjugated verb (e.g., 'lo soy' - I am it) or keep it attached to the infinitive.