to take advantage of; to impose on; to exploit
to enter (an item in a ledger); to make an entry (in an account book)
隙に付け込んだ詐欺師が捕まった。
A con artist who took advantage of a moment of weakness was caught.
相手の親切さに付け込んでいる人は信用できない。
A person who exploits others' kindness cannot be trusted.
人の弱みに付け込む人間は卑劣だ。
Exploiting people's weaknesses is despicable.