Learn Finnish: Jyrsijä livahti koloon. - The rodent slipped into the hole.

It is derived from the verb jyrsiä, which means to gnaw or to nibble. By adding the agent suffix -jä, which acts like the English suffix -er, the word literally translates to 'the gnawer'.

The verb livahtaa translates to 'slipped', but does its ending carry a specific nuance?

Yes, the -htaa ending is frequently used to create 'momentane' verbs. These describe actions that happen very quickly, suddenly, or just briefly. So livahtaa doesn't just mean to move, but specifically to dart, slip, or sneak away quickly and unobtrusively.

I know the word reikä also means 'hole'. Why use kolo here instead?

While reikä usually refers to a puncture or a hole that goes completely through something, like a hole in a shirt, kolo refers to a cavity, nook, or hollowed-out space. Since the rodent is slipping into a hiding place or a burrow, kolo is the correct word to use.