sewenang-wenang=arbitrary - based on random choice or personal whim, rather than any reason or system: an arbitrary decision http://www.oxforddictionaries.com/definition/english/arbitra...

arbitrary (adjective), more arbitrary, most arbitrary
1. Descriptive of decisions made by a person's liking; dependent upon someone's will or pleasure; at the discretion or option of anyone: "The supervisor made an unplanned and arbitrary decision to cancel the meeting." http://wordinfo.info/unit/175/ip:11

Jelas juga arbitrary bersanding atau berkolokasi dengan decision

An arbitrary decision is one not supported by facts or logic.
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&c...

Treatment by Employer
"The treatment of an employee by his employer or supervisor may be so arbitrary and unacceptable to a person of ordinary reasonable sensitivity as to afford justification for the employee to quit the employment [.]" http://www.labor.mo.gov/DES/Appeals/selected_caselaw.asp

Such standards would provide clear guidance to determine the quality of an employee’s work and would prevent arbitrary decisions by a supervisor to punish or fire someone. http://www.goldwaterinstitute.org/article/undisciplined-bure...

Jika yang dimaksud atasan langsung, immediate bisa dipakai dan disandingkan supervisor atau superior.

4 [only before noun]
nearest in relationship or rank
He is my immediate superior (= the person directly above me) in the company. http://oald8.oxfordlearnersdictionaries.com/dictionary/immed...

superior [countable]
someone who has a higher rank or position than you, especially in a job:
He had a good working relationship with his immediate superior (=the person directly above him).
http://www.ldoceonline.com/dictionary/superior_2

by secara implisit merujuk pada 'decisions [that are made] by'. Bentuk jamak atau plural merujuk lazimnya tindakan atau keputusan yang pasti lebih dari satu.