Similarities: clause and brought are monosyllabic words, they have the same vowel sound (klɔːz and brɔːt), they both begin and end with consonants and have two vowels each.
Differences: While clause is a noun that refers to a group of related words with a subject and a verb, brought is the past form of the verb bring which indicates the action of taking or carrying something with us (among other definitions). Besides, clause is spelled differently than brought.