to move slowly nearer to sb, usually from behind, without being seen or heard
creep up on sb
to move slowly nearer to sb, usually from behind, without being seen or heard
Don't creep up on me like that!
creep up on sb
to begin to affect sb, especially before they realize it
Tiredness can easily creep up on you while you're driving.
Definiciones del Oxford Advanced Learner's Dictionary, 9.ª edición