I think "kindred spirits" is a phrase that means friendship. I remember this phrase from the "Anne of Green Gables" books by Lucy Maud Montgomery.
KO or kill
Homework is an 8 letter word starting with h and ending with k.
A favorite musical word of mine that starts with K is kettle drum.
knack, knock, kayak
kronos is a greek word starting with k.
Klutzy is a word that begins with the letter k. It means awkward or clumsy.