A helpful list of antonyms with the same word length for your everyday variable names:

• lo/hi
• up/dn
• rd/wr
• beg/end
• bid/ask
• fst/snd/lst (first/second/last)
• lhs/rhs (left/right hand side)
• src/dst
• top/mid/bot
• get/set
• old/new0
• min/mid/max2
• new/del10
• add/del1
• fix/var
• one/any/all/non/nil
• yay/nay
• give/take
• head/tail
• less/more
• play/stop
• pred/succ
• prev/curr/next2
• push/pull
• this/that0
• true/fake0
• yeah/nope
• east/west
• below/above
• Bible/Koran/Torah
• fresh/stale
• north/south
• start/pause/break0
• sugar/spice
• large/small
• lower/upper
• allow/block
• inner/outer
• accept/reject
• permit/refuse
• permit/forbid
• permitted/forbidden
• create/insert/remove/delete0
• encode/decode/verify
• source/target
• unique/shared
• acquire/release
• antonym/synonym
• diverse/uniform
• include/exclude
• primary/counter
• donation/thievery
• relative/absolute
• producer/consumer
• positive/negative
• increment/decrement
• permanent/temporary

0 C++ keyword, cannot be used as an identifier
1 Python keyword, cannot be used as an identifier
2 Python builtin, should not be used as an unqualified identifier, but ok as member

• get/got/gen (gen for generate)
• width/depth
• length/height

• OK/NG0
• this->/other.
• localhost/127.0.0.1 😂

0 the "NG" initials are commonly used in Japan for "Not Good"

Several [Twitter] [threads] [1].