1) Absorbedly 2) Attentively 3) Carefully 4) Confidentially 5) Familiarly 6) Fixedly 7) In a close manner 8) In an attentive manner 9) In few hands 10) Intimately 11) Keenly 12) Nearly 13) One way to follow someone 14) Warmly 15) With attention to detail 1) Densely 2) Efficiently 3) Firmly 4) Intimately 5) Precisely 6) Thickly 
• (adv.) Secretly; privately. • (adv.) In a close manner.
Close'ly adverb 1. In a close manner. 2. Secretly; privately. [ Obsolete] « That nought she did but wayle, and often steepe Her dainty couch with tears which closely she did weepe. Spenser. » 
[adv] - in a close manner 2. [adv] - in a close relation or position in time or space
adverb in a close manner; `the two phenomena are intimately connected`; `the person most nearly concerned` adverb in a close relation or position in time or space; `the onsets were closely timed`; `houses set closely together`; `was closely involved in monitoring daily progress`