FLUNK
failing, flunk
(noun) failure to reach a minimum required performance; “his failing the course led to his disqualification”; “he got two flunks on his report”
fail, flunk, bomb, flush it
(verb) fail to get a passing grade; “She studied hard but failed nevertheless”; “Did I fail the test?”
Source: WordNet® 3.1
Etymology
Verb
flunk (third-person singular simple present flunks, present participle flunking, simple past and past participle flunked)
(US, ambitransitive) Of a student, to fail a class; to not pass.
(US, transitive) Of a teacher, to deny a student a passing grade.
(US, dated, informal) To shirk (a task or duty).
To back out through fear. (Commonly in the phrase 'flunk it', the 'it' referring to a specific task avoided; sometimes without specific reference describing a person's attitude to life in general.)
Source: Wiktionary
Flunk, v. i. [imp. & p. p. Flunked; p. pr. & vb. n. Flunking.] Etym:
[Cf. Funk.]
Definition: To fail, as on a lesson; to back out, as from an undertaking,
through fear.
Flunk, v. t.
Definition: To fail in; to shirk, as a task or duty. [Colloq. U.S.]
Flunk, n.
Definition: A failure or backing out; specifically (College cant),
Definition: a total failure in a recitation. [U.S.]
Source: Webster’s Unabridged Dictionary 1913 Edition