know what one is doing
Have requisite expertise
To know what one is doing is to have competence or expertise in a particular area.
The phrase usually appears in contexts questioning or affirming someone's capability: Does the new surgeon know what she's doing?
Don't worry—he knows what he's doing.
The negative form suggests incompetence or recklessness: These people don't know what they're doing.
- adeptnessHighly developed ability
- skillfulnessCompetence from practice
- competenceAdequate ability to function
- expertiseSkill from extensive practice
- proficiencySkilled performance level
know-how · know the ropes · old hand · been around the block · purposefulness · craftsmanship · capability · practiced · understanding · comprehension · insight · second nature · dexterity · steady hand · seasoned · mastery · familiarity · savvy
know what one is doingwing it
Act without preparation
fly by the seat of one's pants · play it by ear · shoot from the hip · flail about · muddle through
knows, known, knowing, knowingly, knowledge, knowledgeable, unknowing, unknowingly, unknown