Admittedly, he has some flaws, but overall he is a good leader.

admittedly 是副词，由动词 admit（承认）加上后缀 -ed 和 -ly 构成。admit 意思是"承认、准许"，-ed 后缀构成形容词 admitted（被承认的），-ly 后缀将形容词变为副词。admittedly 表示"无可否认地、诚然"，用于承认某个事实或观点。