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diligent: diligent: [14] The underlying meaning of diligent is ‘loving’. It comes via Old French diligent from the present participial stem of Latin dīligere ‘esteem highly, love’. This was a compound verb formed from the prefix dis- ‘apart’ and legere ‘choose’ (source of English elect, neglect, and select), and so originally meant literally ‘single out’. It gradually passed semantically via ‘love’ to ‘attentiveness’, ‘carefulness’, and finally ‘steady effort’.
=> elect, neglect, select
diligence (n.): mid-14c., from Old French diligence "attention, care; haste, speed," from Latin diligentia "attentiveness, carefulness," from diligentem (nominative diligens) "attentive, assiduous, careful," originally present participle of diligere "single out, value highly, esteem, prize, love; aspire to, be content with, appreciate," originally "to pick out, select," from dis- "apart" (see dis-) + legere "choose, gather" (see lecture (n.)).

Sense evolved from "love" through "attentiveness" to "carefulness" to "steady effort." From the secondary French sense comes the old useage of diligence for "public stage coach" (1742; dilly for short), from a French shortening of carrosse de diligence.
pick (v.): early 13c., picken "to peck;" c. 1300, piken "to work with a pick," probably representing a fusion of Old English *pician "to prick," (implied by picung "a piercing, pricking," an 8c. gloss on Latin stigmata) with Old Norse pikka "to prick, peck," both from a Germanic root (source also of Middle Dutch picken, German picken "to pick, peck"), perhaps imitative. Influence from Middle French piquer "to prick, sting" (see pike (n.2)) also is possible, but that French word generally is not considered a source of the English word. Related: Picked; picking.

Meaning "to eat with small bites" is from 1580s. The meaning "to choose, select, pick out" emerged late 14c., from earlier meaning "to pluck with the fingers" (early 14c.). Sense of "to rob, plunder" (c. 1300) weakened to a milder sense of "steal petty things" by late 14c. Of forcing locks with a pointed tool, by 1540s. Meaning "to pluck (a banjo)" is recorded from 1860. To pick a quarrel, etc. is from mid-15c.; to pick at "find fault with" is from 1670s. Pick on "single out for adverse attention" is from late 14c.; pick off "shoot one by one" is recorded from 1810; baseball sense of "to put out a runner on base" is from 1939. Also see pick up. To pick and choose "select carefully" is from 1660s (choose and pick is attested from c. 1400).
select (adj.): 1560s, from Latin selectus, past participle of seligere "choose out, single out, select; separate, cull," from se- "apart" (see secret (n.)) + legere "to gather, select" (see lecture (n.)). The noun meaning "a selected person or thing, that which is choice" is recorded from c. 1600. New England selectman first recorded 1640s.
select (v.): "to single out one or more out of a number of things of the same kind," 1560s, from select (adj.) or from Latin selectus. Related: Selected; selecting.