The Plain English Campaign (PEC) says no-one needs to be told that police are "protecting our communities by reducing crime and anti-social behaviour", "keeping our communities safe and reassured" or "serving our communities, protecting them from harm".
The group says the police service has nothing to sell and the word "police" tells people all they need to know.
Most forces attach slogans to their names on websites and some add slogans to vehicles.
Humberside Police uses the slogan "Protecting Communities Targeting Criminals", while in North Yorkshire the force uses "Delivering modern policing in a traditional way".
Both forces defended their use of the slogans.
A spokeswoman for North Yorkshire Police said: "We have worked recently to strengthen our brand and we have now adopted the 'Safer Neighbourhoods' brand across the entire organisation.
"The slogan 'Delivering modern policing in a traditional way' is the vision of the chief constable and accompanies the branding on most printed external literature and publications."
Her counterpart at Humberside Police said: "We use various slogans with a view to people being familiar with the exact scheme or initiative we are referring to."
South Yorkshire Police Chief Constable Meredydd Hughes decided to drop the "Justice With Courage" slogan over three years ago, and this is being phased out.
A force spokesman said: "We felt it wasn't necessarily clear what it meant and if it's not, what's the point? As far as we are concerned South Yorkshire Police should say it all; we are a police force at the end of the day and we don't feel the need to add to the name."
A PEC spokeswoman said: "Some are just meaningless. Northumbria's slogan is 'Total Policing'. What does that mean? Do some police forces operate 'partial policing'?"
She added: "It's not just about wasting words – there has to be a cost to the public."