Why is it der Gigant?

Gigant ends in -ant, and almost all nouns ending in -ant are masculine: in a German dictionary, 94% of them take der.

All nouns ending in -ant
Sense 1
der

Meaning

[1] giant

[1] Riese

[2] Mythology: Titan

[2] Mythologie: Titan

[3] Person or institution with extraordinary properties or skills

[3] Person oder Institution mit außergewöhnlichen Eigenschaften oder Fähigkeiten

Examples

[1] In Greek mythology there were also gigantees

[1] In der griechischen Mythologie gab es auch Giganten.

[2] Microsoft is a giant among the software company

[2] Microsoft ist ein Gigant unter den Softwarefirmen.
More source examples (1)

These dictionary examples can include historical and less common uses.

[3]

[3]

Declension

1 Singular Plural
Nominativ der Gigant die Giganten
Genitiv des Giganten der Giganten
Dativ dem Giganten den Giganten
Akkusativ den Giganten die Giganten

Pronunciation

Dictionary entries include material from Wiktionary. Wiktionary