a few police, not many police, a few police officers, etc
The noun police is unusual. Police is usually treated as plural, and has no singular form, except maybe a 'police officer', or a policeman.
The word originated from the word tadpole. As a tadpole is small. And the meaning for the word tad is small or a small amount.
small
smidget
A pinch
Pinch, trace
Jot
Measure.
iota
A sliver? A portion/ration/piece/pinch
The word is negligible, and it means "too small in amount to be of importance"
Titch is British slang for a small amount.
trace