とことん
tokoton

Noun

1. the very end; finish

Onomatopoeia
Noun
Adverb

2. to the very end; to the last; thoroughly; completely; fully

Onomatopoeia
その いぬ みつこうとしたときに、首 くび おさえつけてとことん しかりつけた。
sono inuga kamitsukōto shita tokini kubio osaetsukete tokoton shikaritsuketa.
When the dog tried to bite me, I held him down by the neck and thoroughly scolded him.