The one who / those who (sá sem, þeir sem)

"The One Who": Singular

To talk about someone who fits a certain description—like an ideal job candidate—pair a demonstrative pronoun with the relative particle sem (who/that). Choose the pronoun that matches the grammatical gender of the person you are referring to:

GenderPhraseMeaning
Masculinesá semthe one who
Femininesú semthe one who
He is the one who shows initiative.
Hann er sá sem sýnir frumkvæði.
She is the one who has ambition.
Hún er sú sem hefur metnað.

You can use these phrases as the subject of a larger sentence, which is useful for describing what happens to a person who has specific traits:

The one who gets the position is usually a qualified applicant.
Sá sem fær stöðuna er venjulega hæfur umsækjandi.

"Those Who": Plural

When referring to a group of people, use the plural demonstrative pronouns before sem.

GenderPhraseMeaning
Masculine / Mixedþeir semthose who
Feminineþær semthose who
Neuterþau semthose who

Remember that þeir is the grammatical default for mixed-gender groups of people.

Those who have ambition choose a demanding position.
Þeir sem hafa metnað velja krefjandi stöðu.
Those who show initiative always become managers.
Þær sem sýna frumkvæði verða alltaf stjórnendur.
Those who do not have ambition never get the position.
Þau sem hafa ekki metnað fá aldrei stöðuna.

Describing Specific Nouns with "Sem"

If you explicitly name the person or thing, you do not need the demonstrative pronoun (, , etc.). Place sem directly after the noun to mean "the [noun] who" or "the [noun] that":

For example, the applicant who got the position is qualified.
Til dæmis er umsækjandinn sem fékk stöðuna hæfur.
Initiative is exactly the quality that we need.
Frumkvæði er einmitt eiginleikinn sem okkur vantar.