1) Adagio 2) Adverb 3) Idly 4) Laboriously 5) Largo 6) Late 7) Lazily 8) Lento 9) Lethargically 10) Tardily 11) Unenergetically 1) Easy 2) Hardly with rapidity 3) How a snail does things 4) How to start a czardas 5) In music 6) In stages 7) Inchmeal 8) Increasingly 9) Larghetto 10) Largo 11) Like a snail 12) Little by little 13) Progressively 14) Regularly 15) Slow 16) Slowly but surely 17) Steadily 18) Step by step 19) Tardily 
• (adv.) In a slow manner; moderately; not rapidly; not early; not rashly; not readly; tardly.
Moving at less than 15 knots
Slow'ly adverb In a slow manner; moderately; not rapidly; not early; not rashly; not readly; tardly. 
[adv] - without speed
easy 2 tardily adverb without speed (`slow` is sometimes used informally for `slowly`); `he spoke slowly`; `go easy here--the road is slippery`; `glaciers move tardily`; `please go slow so I can see the sights`