Useful words for a thesis...

In order of most to least critical (and strong to weak):

Random posh getting-right-to-the-bottom-of-things words
Illuminate
Rationalise
Elucidate

Something-to-prove words
Justify
Prove
Demonstrate
Confirm
Show
Support [the notion that]
Indicate
Suggest
Claim

Digging deeper words
Analyse
Examine
Explore
Seek to understand
Probe
Question
Discuss
Assess

Describing words
Illustrate
Clarify
Define
Explain
Describe