What is the definition of the word underestimate?

Match these items. 1. academic language letter or letters added to the end of a word that changes the part of speech and meaning of the root word 2. social language language spoken with peers in social settings 3. suffix language spoken in academic settings 4. root word letter or letters added to the beginning or end of a word, root, or stem, or the middle of a word, to modify its meaning 5. prefix initial word before adding a suffix and/or prefix 6. affix letter or letters added to the beginning of a word that changes the meaning of the word