under someone's thumb

Under another's authoritarian control; continually forced to submit to another's will. They seem happy when they're out and about, but I hear that Johnny is under his husband's thumb at home. Although the job paid well, I couldn't stand the way I was under the boss's thumb.

Controlled or dominated by someone, as in He's been under his mother's thumb for years. The allusion in this metaphoric idiom is unclear, that is, why a thumb rather than a fist or some other anatomic part should symbolize control. [Mid-1700s]

COMMON If someone is under another person's thumb, the second person controls them. He's completely under his mother's thumb. It's a wonder he dared move out of his room without her permission. National television is firmly under the thumb of the president. Note: You can also say that someone is under the thumb. Ian told the court how his wife kept him under the thumb during their seven-year marriage.

Under a person’s influence or power. Why the thumb should have been singled out as a symbol of control or power is open to speculation, but it was, and as early as the mid-eighteenth century. “Authors . . . are under the thumb of booksellers,” wrote B. H. Malkin in his translation of Gil Blas (1809). The situation has not changed since Malkin’s day, and the cliché is also very much alive.