I would ask my mum what a word meant and she'd ask me the context I'd read/heard it in, and then ask me what I thought it meant. She taught me to break the word up into syllables to see if there were other words I did know the definition of that shared those syllables and whether I could work it out from there.
If I couldn't then I had to look it up in the dictionary - we had a big, heavy Collins one from memory. Big blue hardback.
I remember being annoyed and just whining that she should just tell me the definition. But it was clearly better for me to learn that way.
Edit: I just re read and you said bad words. Mum would usually give me a clipped, child friendly definition and advice not to repeat it in polite company.