Casual
Part of speech: noun
Definition: A worker who is only working for a company occasionally, not as its permanent employee.
Part of speech: adjective
Definition: Happening by chance. Coming without regularity; occasional or incidental. Employed irregularly Careless. Happening or coming to pass without design. Informal, relaxed. Designed for informal use.
Example sentence: Children are not casual guests in our home. They have been loaned to us temporarily for the purpose of loving them and instilling a foundation of values on which their future lives will be built.
Nonchalant
Part of speech: adjective
Definition: Casually calm and relaxed.Indifferent; unconcerned; behaving as if detached.