Green’s Dictionary of Slang

whale n.

[joc. uses of SE, the size of the creature]

1. [late 18C] an important or influential person.

2. [mid-19C–1920s] (US, orig. campus) an exceptionally brilliant scholar.

3. [late 19C+] (US) an exceptionally large or fat person.

4. [late 19C-1930s] usu. as a whale for..., a fanatic, an obsessive, a fan of.

5. [late 19C–1910s] (Aus.) an exceptional performer in any given discipline; also ironic use; thus a whale at/on; whale of a...

6. (US) a heavy bettor.

In phrases

whale in the bay (n.) (Aus.)

1. [1930s] someone who has money to spend and uses it on the assembled company.

2. [1980s+] ‘a major influence at work behind the scenes’ (Wilkes).

whale of a... (also whaleuva)

1. [late 19C+] a general intensifier, whether positive or negative, hell of a, a under hell n.

2. [1910s+] an exceptional person.

whale of a lot

[20C+] a large amount of, a great deal of.

whale of a time (n.)

[late 19C+] a riotous evening, an extremely enjoyable occasion; occas. negative use.

SE in slang uses

In compounds

whale and whitewash (n.)

[1930s] (UK tramp) fish in white sauce.

whale belly (n.)

[1930s] (US tramp) a steel coal-car.

In phrases

play the whale (v.) [echoic + ? the biblical story of Jonah, who was vomited up by a whale]

[1960s–70s] (Aus.) to vomit.