Real Dictionary

hit and miss
done carelessly or without proper planning, so equally likely to fail or succeed
adjective: If something is hit and miss or hit or miss, it is sometimes successful and sometimes not.

hit and miss in British English
adjective: random; haphazard
adjective: unpredictable; sometimes successful, sometimes unsuccessful

hit-and-miss in American English
resulting in both successes and failures
adjective: sometimes successful or rewarding and sometimes not