Big head and Self-conceit

Self-conceit and big head are semantically related. In some cases you can use "Self-conceit" instead a noun phrase "Big head".

Self-conceit noun - An often unjustified feeling of being pleased with oneself or with one's situation or achievements.

Big head and self-conceit are semantically related. Sometimes you can replace phrase "Big head" with "Self-conceit", this phrases are similar.