To/tə,tu/ Definition 1 of 5Pro Tip 1/3Infinitive Marker Marks the base form of verbs, showing purpose or intent without specifying time. She loves to dance. Pro Tip 2/3After Adjectives Follows adjectives when describing a reaction or feeling about something. I'm happy to help. Pro Tip 3/3Fixed Expressions Often found in set phrases that don't change, like 'nice to meet you'. It's hard to say.