Can anyone give a list of the different words used and perhaps point out the differences in emphasis or exact meaning? For instance, do all the words mean exactly the same or do particular ones emphasise a different quality of mindfulness?
The Pali word is Sati, which derives from the verb Sarati, which literally means to remember. If you look at how the word is actually used in the texts, there seems to be three distinct senses of the term.
The first sense is the most general, and it just means memory, or the ability to recall events and information. This isn't a major meaning of the term Sati in the Buddhist texts, but it does show up occasionally.
In a second sense, Sati has a more specific meaning of focusing the mind on an object. This is more commonly used in the form of a suffix, so for example Ānāpānasati means setting the mind on the Ānā and pāna, the in-breath and the out-breath.
In the last sense, it has a much more specific meaning. It means the setting of the mind on an object of ultimate reality, meaning setting the mind on direct experience itself, which can be divided up into four categories of body,feeling, mind, and dhammas, meaning physical sensation, the experience of something as pleasant, unpleasant, or neither, awareness, and various mental qualities that occur in the mind such as emotions.
This list is called the four Satipatthana, and the correct setting of the mind on them is called Samma-Sati, or right mindfulness, which is the seventh factor of the Noble Eightfold Path. The standard definition found in many places in the Suttas is as follows:
And what is right mindfulness? There is the case where a monk remains focused on the body in & of itself — ardent, alert, & mindful — putting aside greed & distress with reference to the world. He remains focused on feelings in & of themselves... the mind in & of itself... mental qualities in & of themselves — ardent, alert, & mindful — putting aside greed & distress with reference to the world. This is called right mindfulness.
There are other aspects of the definition which the Ven. Yuttadhammo has already mentioned in his answer as well
Actually, the only good translation I can think of for the English "mindfulness" is Sampajañña. sam = full, pa = full, jañña = knowledge (or awareness).
Another potential candidate is yoniso (to the source) manasikara (minding).
What is pretty clear is that sati does not translate to mindfulness. sati comes from the root /sar, which means to remember or recollect. It doesn't mean to be mindful; translations like "mindfulness of the Buddha" show this to be a silly choice. "remembrance" is probably a better one.
As Bhikkhu Bodhi notes:
Even the word sati, rendered mindfulness, isn’t unproblematic. The word derives from a verb, sarati, meaning “to remember,” and occasionally in Pali sati is still explained in a way that connects it with the idea of memory. But when it is used in relation to meditation practice, we have no word in English that precisely captures what it refers to. An early translator cleverly drew upon the word mindfulness, which is not even in my dictionary. This has served its role admirably, but it does not preserve the connection with memory, sometimes needed to make sense of a passage.
And there is a good article on Theravadin that I think agrees with the above both on sati and sampajañña:
By now you will wonder how the term sati became so established as “mindfulness”. Well, mindfulness will be a result of ones practice of noting, especially during the noting…during the seeing. However, the best term translated as mindfulness is in fact a separate pali word called “sam-pajanna“, lit. ‘to know together with’
According to TamilCube: appamāda, paṭisaṅkhāna (http://dictionary.tamilcube.com/pali-dictionary.aspx)
@Yuttadhammo I'm not sure that we can say that yoniso manasikara would be an alternative. As I understand it yoniso manasikara is something different. See: http://www.meditationboonkan.org/Vipassana.htm
Just to answer my own question
- appamāda as @Medhini says. This having the quality of heedfulness
- atappa giving the sense of ardency
Both these I've got from wikipedia to be honest but I just wanted to complete all the possible translations that I could recall to complete the question