Þökk is a giantess in Norse mythology

Norse mythology

Norse mythology, a subset of Germanic mythology, is the overall term for the myths, legends and beliefs about supernatural beings of Norse pagans. It flourished prior to the Christianization of Scandinavia, during the Early Middle Ages, and passed into Nordic folklore, with some aspects surviving...

, presumed to be Loki

Loki

In Norse mythology, Loki or Loke is a god or jötunn . Loki is the son of Fárbauti and Laufey, and the brother of Helblindi and Býleistr. By the jötunn Angrboða, Loki is the father of Hel, the wolf Fenrir, and the world serpent Jörmungandr. By his wife Sigyn, Loki is the father of Nari or Narfi...

 in disguise, who refuses to weep for the slain Baldr, thus forcing him to stay in Hel

Hel (realm)

In Norse mythology, Hel, the location, shares a name with Hel, a female figure associated with the location. In late Icelandic sources, varying descriptions of Hel are given and various figures are described as being buried with items that will facilitate their journey to Hel after their death...

.

Prose Edda

After Baldr was killed, Hermóðr

Hermóðr

Hermóðr the Brave is a figure in Norse mythology, the son of god Odin.-Prose Edda:Hermóðr appears distinctly in section 49 of the Prose Edda book Gylfaginning. There, it is described that the gods were speechless and devastated at the death of Baldr, unable to react due to their grief...

 rode to Hel. Hel

Hel (being)

In Norse mythology, Hel is a being who presides over a realm of the same name, where she receives a portion of the dead. Hel is attested in the Poetic Edda, compiled in the 13th century from earlier traditional sources, and the Prose Edda, written in the 13th century by Snorri Sturluson...

, the ruler of the realm of the same name

Hel (realm)

In Norse mythology, Hel, the location, shares a name with Hel, a female figure associated with the location. In late Icelandic sources, varying descriptions of Hel are given and various figures are described as being buried with items that will facilitate their journey to Hel after their death...

, agreed that Baldr should go back to the living if all things in the world wept for him. So the Æsir

Æsir

In Old Norse, áss is the term denoting a member of the principal pantheon in Norse paganism. This pantheon includes Odin, Frigg, Thor, Baldr and Tyr. The second pantheon comprises the Vanir...

sent messengers all over the word, and all wept for him, but:

"Then, when the messengers went home, having well wrought their errand, they found, in a certain cave, where a giantess sat: she called herself Thökk. They prayed her to weep Baldr out of Hel; she answered:

Thökk will weep

waterless tears

For Baldr's bale-fare;

Living or dead,

I loved not the churl's son;

Let Hel hold to that she hath!

And men deem that she who was there was Loki Laufeyarson, who hath wrought most ill among the Æsir."

—Gylfaginning (49), Brodeur's translation