Definir means 'to define', and it is a regular -ir verb useful for explanation and analysis. ¿Cómo defines el éxito? (how do you define success?), es difícil de definir (it's hard to define). Because defining terms and concepts is part of structured, higher-level writing, definir adds useful range to essays. The reflexive definirse can mean to take a clear position. As a regular -ir verb the conjugation is predictable, and the related adjective definido ('defined') and noun la definición are easy to learn alongside it.
Quick facts
Definir (to define) is a regular -ir verb.
Real sentences across different tenses — the kind of thing you'd actually say or write.
¿Cómo defines el éxito? (how do you define success?).
Useful for explaining concepts in essays.
Reflexive definirse (to take a clear position).
La definición, definido.
Fixed expressions worth knowing — they come up in listening, reading and writing tasks.
Idiomatic expressions
Definir is a regular verb. Make sure you know the endings for each tense — especially the preterite and subjunctive, which is where marks are most often lost.
definir is a regular -ir verb — it follows the standard -ir pattern in every tense. That makes it a good one to drill: if you know definir, you know the template for all regular -ir verbs.
Type conjugations from memory and get instant feedback. That's how you actually build the automatic recall the exam needs — not from reading tables.
Practice definir now →Three questions. Press Enter to check each answer.
yo: defino, tú: defines, él: define, nosotros: definimos, vosotros: definís, ellos: definen
Definir is a regular -ir verb following the standard -ir pattern.
Use definir in multiple tenses to show range — present, preterite and future at minimum. This is a key criterion for higher GCSE marks.
Verbs that are easy to confuse with definir or that behave like it.
This reference is written for UK GCSE and A-Level Spanish learners and their teachers. It is designed for exam revision: every form is checked against standard conjugation rules, and the examples reflect the registers and topics that come up in the AQA, Edexcel and Eduqas specifications. Definir is a high-frequency verb and appears often in exam papers. For active recall, use the free practice tool rather than only reading the tables.
Last updated 2 August 2026. Written by Daniel Holmes for GCSE & A-Level Spanish students.