Meaning of “sink sth into sth” - Learner’s Dictionary

sink sth into sth

phrasal verb with sink us uk /sɪŋk/ verb past tense and past participle sank, also US sunk, past participle sunk

to spend a large amount of money in a business or other piece of work:

Millisat has already sunk $25 million into the Hong Kong project.

(Definition of “sink sth into sth” from the Cambridge Learner’s Dictionary © Cambridge University Press)