Meaning of Islamic words

Q: What is the difference between israaf and tabzeer since both translate as wasting? 

Q: Is it okay to say Jazakallah and Wa iyyak to elders (e.g. ustaad, parents)?

Q: What is the difference between ‘bi iznillah’ and ‘Insha-Allah’and what could be the sources of these two phrases?

Q: I'd like to know what does haamidan wa musalliyan mean? And why do your'll write it? Is it a sunnah?

Q: Who is a faasiq?

If your friends know you do some type of sin, are you considered a faasiq?

Q: What is the law of fitnah?

What is the name of people who make fitnah?

Q: What is tafarrud?

Q: Is the interpretation and symbolism of dreams the same as that for kashf/ilhaam? Or is kashf/ilhaam interpretation entirely separate?

Q: What is the rulling about zaalims (oppressors), can you explain the definition of an oppressor?

Q: Is saying jazakAllah in Islam?