slow

Concise Oxford English Dictionary © 2008 Oxford University Press:
slow/sləʊ/

▶adjective

• 1 moving or capable of moving only at a low speed.

  ■ lasting or taking a long time.

• 2 (of a clock or watch) showing a time earlier than the correct time.

• 3 not prompt to understand, think, or learn.

• 4 uneventful and rather dull.

  ■ (of business) with little activity; slack.

• 5 Photography (of a film) needing long exposure.

• 6 (of a fire or oven) burning or giving off heat gently.

▶verb (often slow down/up) reduce one's speed or the speed of a vehicle or process.

■ live or work less actively or intensely.

– phrases
slow but (or and) sure not quick but achieving the required result eventually.

– derivatives
slowish adjective,
slowly adverb,
slowness noun.

– origin OE slāw ‘slow-witted, sluggish’, of Gmc origin.

usage: Slow is normally used as an adjective (a slow learner). It is also used as an adverb in certain contexts, including compounds such as slow-acting and in the expression go slow. Other adverbial use (e.g. he drives too slow) is informal and non-standard and in such contexts slowly should be used instead.